DP Chemistry Questionbank

Which species has bond angles of 90°?

A. AlCl₄^-

B. $\text{I}$Cl₄^-

C. NH₄⁺

D. SiCl₄

(i) Sketch a graph of pH against volume of a strong base added to a weak acid showing how you would determine pK_a for the weak acid.

(ii) Explain, using an equation, why the pH increases very little in the buffer region when a small amount of alkali is added.

Standard electrode potentials are measured relative to the standard hydrogen electrode. Describe a standard hydrogen electrode.

(i) Uranium hexafluoride, UF₆, is used in the uranium enrichment process that produces fuel for nuclear reactors.

State the molecular shape of uranium hexafluoride.

(ii) Explain why uranium dioxide, UO₂, has a very high melting point whereas uranium hexafluoride vapourises easily into gas.

Explain the mechanism of the reaction between chloroethane and aqueous sodium hydroxide, $\mathrm{NaOH} \left(\mathrm{aq}\right)$, using curly arrows to represent the movement of electron pairs.

Propanone can be synthesized in two steps from propene. Suggest the synthetic route including all the necessary reactants and steps.

In a titration, $25.00 {\mathrm{cm}}^3$ of vinegar required $20.75 {\mathrm{cm}}^3$ of $1.00 \mathrm{mol} {\mathrm{dm}}^{-3}$ potassium hydroxide to reach the end-point.

Calculate the concentration of ethanoic acid in the vinegar.

What is the charge on the iron(III) complex ion in [Fe(OH)₂(H₂O)₄]Br?

A.     0

B.     1+

C.     2+

D.     3+

Formulate an equation for the oxidation of nickel(II) sulfide to nickel(II) oxide.

Use your answers to (c)(i) and (c)(ii), to determine the temperature, in °C, at which the decomposition of liquid tetracarbonylnickel to nickel and carbon monoxide becomes favourable.

(If you did not get answers to (c)(i) and (c)(ii), use $-500\text{ J}{\text{K}}^{-1}$ and $-200\text{ kJ}$ respectively but these are not the correct answers.)

Vision is dependent on retinol (vitamin A) present in retina cells. Retinol is oxidized to the photosensitive chemical 11-cis-retinal and isomerizes to 11-trans-retinal on absorption of light.

Outline how the formation of 11-trans-retinal results in the generation of nerve signals to the brain.

Describe what happens to plane-polarized light when it passes through a solution of an optically active compound.

Calculate the Gibbs free energy, ΔG ^θ, in kJ, which is released by the corrosion of 1 mole of iron. Use section 1 of the data booklet.

The following mechanism is proposed for the reaction.

Identify the rate determining step giving your reason.

Deduce what information can be obtained from the ¹H NMR spectrum.

Estimate the H−N−H bond angle in methanamine using VSEPR theory.

The graph represents the first ten ionisation energies (IE) of an element.

What is the element?

A. O

B. S

C. Ne

D. Cl

Draw the Lewis (electron dot) structures of PF₃ and PF₅ and use the VSEPR theory to deduce the molecular geometry of each species including bond angles.

1.0 mol each of sulfur dioxide, oxygen, and sulfur trioxide are in equilibrium.

$2{\mathrm{SO}}_2 \left(\mathrm{g}\right)+{\mathrm{O}}_2 \left(\mathrm{g}\right)\rightleftharpoons 2{\mathrm{SO}}_3 \left(\mathrm{g}\right)$

Which change in the molar ratio of reactants will cause the greatest increase in the amount of sulfur trioxide?

Assume volume and temperature of the reaction mixture remain constant.

Explain why the major organic product is 2-bromopropane and not 1-bromopropane.

Explain, using equations, how the presence of ${\text{CCl}}_{\text{2}}{\text{F}}_{\text{2}}$ results in a chain reaction that decreases the concentration of ozone in the stratosphere.

Calculate the cell potential using section 24 of the data booklet.

Which molecule contains a chiral carbon?

A.     CH₃CH₂CHBrCH₂CH₃

B.     CH₃CH₂CHBrCH₃

C.     CH₂BrCH(CH₃)CH₂Br

D.     CH₃CH₂CH₂CH₂CH₂Br

1.0 mol of N₂(g), 1.0 mol of H₂(g) and 1.0 mol of NH₃(g) are placed in a 1.0 dm³ sealed flask and left to reach equilibrium. At equilibrium the concentration of N₂(g) is 0.8 mol dm⁻³.

N₂(g) + 3H₂(g) $\rightleftharpoons$ 2NH₃(g)

What are the equilibrium concentration of H₂(g) and NH₃(g) in mol dm⁻³?

Calculate the standard entropy change, ΔS^Θ, in J K⁻¹, for the reaction in (ii) using section 12 of the data booklet.

Draw the structure of the intermediate formed stating its shape.

Predict the number of ¹H NMR signals, and splitting pattern of the –CH₃ seen for propanone (CH₃COCH₃) and propanal (CH₃CH₂CHO).

The standard electrode potential of zinc can be measured using a standard hydrogen electrode (SHE).

Draw and annotate the diagram to show the complete apparatus required to measure the standard electrode potential of zinc.

Sketch the pH curve for the titration of 25.0 cm³ of ethylamine aqueous solution with 50.0 cm³ of butanoic acid aqueous solution of equal concentration. No calculations are required.

The rate expression for the reaction is: rate = k [NO]²[O₂].

2NO (g) + O₂ (g) → 2NO₂ (g)

Which mechanism is not consistent with this rate expression?

What is the number of sigma (σ) and pi (π) bonds in the molecule (NC)₂C=C(CN)₂?

Which compound produces the following ¹H NMR spectrum?

^{[Spectral Database for Organic Compounds, SDBS. SDBS Compounds and Spectral Search. [graph] Available at:
https://sdbs.db.aist.go.jp [Accessed 3 January 2019].]}

A.  propanal

B.  propanone

C.  propane

D.  methlypropane

Calculate the standard potential, in V, of a cell formed by magnesium and steel half-cells. Use section 24 of the data booklet and assume steel has the standard electrode potential of iron.

Calculate the entropy change for the Haber–Bosch process, in J mol^–1K^–1 at 298 K. Use your answer to (b)(i) and section 1 of the data booklet.

Mg(OH)⁺ is a complex ion, but Mg is not regarded as a transition metal. Contrast Mg with manganese, Mn, in terms of one characteristic chemical property of transition metals, other than complex ion formation.

Calculate the concentration, in mol dm^–3, of ammonia molecules in the solution with pH = 9.3. Use section 21 of the data booklet.

Iron(II) is oxidized by bromine.

2Fe²⁺ (aq) + Br₂ (l) $\rightleftharpoons$ 2Fe³⁺ (aq) + 2Br⁻ (aq)

Calculate the E^⦵_cell, in V, for the reaction using section 24 of the data booklet.

Calculate the Gibbs free energy change, ΔG^⦵, in kJ mol⁻¹, for the reaction at 298 K. Use section 1 of the data booklet.

Identify the number of sigma and pi bonds in HCN.

Explain the mechanism of the reaction between 1-bromopropane, CH₃CH₂CH₂Br, and aqueous sodium hydroxide, NaOH (aq), using curly arrows to represent the movement of electron pairs.

An aqueous solution containing high concentrations of both NH₃ and NH₄⁺ acts as an acid-base buffer solution as a result of the equilibrium:

NH₃ (aq) + H⁺ (aq) $\rightleftharpoons$ NH₄⁺ (aq)

Referring to this equilibrium, outline why adding a small volume of strong acid would leave the pH of the buffer solution almost unchanged.

Outline why both C to O bonds in the conjugate base are the same length and suggest a value for them. Use section 10 of the data booklet.

The organic product is not optically active. Discuss whether or not the organic product is a racemic mixture.

Suggest a suitable indicator for the titration, using section 22 of the data booklet.

An aqueous solution of silver nitrate, AgNO₃ (aq), can be electrolysed using platinum electrodes.

Formulate the half-equations for the reaction at each electrode during electrolysis.

Cathode (negative electrode):

Anode (positive electrode):

State what the presence of alternative Lewis structures shows about the nature of the bonding in the molecule.

Which equation represents the standard enthalpy of atomization of bromine, Br₂?

A. $\frac{1}{2}$Br₂ (l) → Br (g)

B. Br₂ (l) → 2Br (g)

C. Br₂ (l) → 2Br (l)

D. $\frac{1}{2}$Br₂ (l) → Br (l)

The following equation represents the dissociation of water at 25 °C.

2H₂O (l) $\rightleftharpoons$ H₃O⁺ (aq) + OH⁻ (aq)        ΔH = +56 kJ

Which changes occur as the temperature increases?

A. [H₃O⁺] increases and pH will decrease.

B. [H₃O⁺] decreases and pH will increase.

C. [H₃O⁺] increases and pH will increase.

D. [H₃O⁺] decreases and pH will decrease.

Two more trials (2 and 3) were carried out. The results are given below.

Determine the rate equation for the reaction and its overall order, using your answer from (b)(i).

Rate equation: 

Overall order: 

Determine the rate expression from the results, explaining your method.

Which is the ¹H NMR spectrum of tetramethylsilane, TMS, (CH₃)₄Si?

Deduce the half-equation for the formation of the gas identified in (c)(iii).

Calculate the ratio of [A⁻] : [HA] in a buffer of pH 6.0 given that pK_a for the acid is 4.83, using section 1 of the data booklet.

A concentration cell is an example of an electrochemical cell.

(i) State the difference between a concentration cell and a standard voltaic cell.

(ii) The overall redox equation and the standard cell potential for a voltaic cell are:

Zn (s) + Cu²⁺ (aq) → Zn²⁺ (aq) + Cu (s)     E^θ_cell = +1.10 V

Determine the cell potential E at 298 K to three significant figures given the following concentrations in mol dm⁻³:

[Zn²⁺] = 1.00 × 10⁻⁴       [Cu²⁺] = 1.00 × 10⁻¹

Use sections 1 and 2 of the data booklet.

(iii) Deduce, giving your reason, whether the reaction in (b) (ii) is more or less spontaneous than in the standard cell.

(i) Draw diagrams to show how sigma (σ) and pi (π) bonds are formed between atoms.

(ii) State the number of sigma (σ) and pi (π) bonds in propane and propene.

Which compound with the molecular formula ${\mathrm{C}}_4{\mathrm{H}}_8\mathrm{O}$ has this high resolution ${}_1\mathrm{H} \mathrm{NMR}$?

From: libretexts.org. Courtesy of Chris Schaller, Professor (Chemistry)
at College of Saint Benedict/Saint John’s University.

A.  but-3-en-2-ol, ${\mathrm{CH}}_2=\mathrm{CHCH}\left(\mathrm{OH}\right){\mathrm{CH}}_3$

B.  butanal, ${\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{CH}}_2\mathrm{CHO}$

C.  butanone, ${\mathrm{CH}}_3{\mathrm{COCH}}_2{\mathrm{CH}}_3$

D.  but-3-en-1-ol, ${\mathrm{CH}}_2={\mathrm{CHCH}}_2{\mathrm{CH}}_2\mathrm{OH}$

What will be the major product in the reaction between but-1-ene and $\mathrm{Hbr}$?

A.  2-bromobut-1-ene

B.  1-bromobut-1-ene

C.  2-bromobutane

D.  1-bromobutane

Which statement is correct when a zinc spoon is electroplated with silver?

A.  The cathode (negative electrode) is made of silver.

B.  The anode (positive electrode) is the zinc spoon.

C.  The anode (positive electrode) is made of silver.

D.  The electrolyte is zinc sulfate solution.

Which of these statements are correct?

I. Zinc is not a transition element.
II. Ligands are Lewis bases.
III. Manganese(II) chloride is paramagnetic.

A.  I and II only

B.  I and III only

C.  II and III only

D.  I, II and III

Calculate the standard free energy change, $∆{\mathrm{G}}^{⦵}$, in $\mathbf{kJ}$, for the cell using sections 1 and 2 of the data booklet.

Predict, giving a reason, how an increase in temperature affects the potential of this cell.

The table gives rate data for the reaction in a suitable solvent.

C₄H₉Br + OH⁻ → C₄H₉OH + Br⁻

Which statement is correct?

A.     The rate expression is rate = k [C₄H₉Br] [OH⁻].

B.     The rate increases by a factor of 4 when the [OH⁻] is doubled.

C.     C₄H₉Br is a primary halogenoalkane.

D.     The reaction occurs via S_N1 mechanism.

The student then carried out the experiment at other acid concentrations with all other conditions remaining unchanged.

Determine the relationship between the rate of reaction and the concentration of acid and the order of reaction with respect to hydrogen ions.

When the concentration of iodine is varied, while keeping the concentrations of acid and propanone constant, the following graphs are obtained.

Deduce, giving your reason, the order of reaction with respect to iodine.

Identify, from the table, a non-vanadium species that can reduce VO²⁺(aq) to V³⁺(aq) but no further.

Comment on the spontaneity of this reaction by calculating a value for $\mathrm{\Delta }{G}^{\theta }$ using the data given in (b) and in section 1 of the data booklet.

Calculate a value for $\mathrm{\Delta }{H}^{\theta }$ in kJ.

The Born-Haber cycle for potassium oxide is shown below:

Which expression represents the lattice enthalpy in kJ mol^–1?

A.     –361 + 428 + 838 + 612

B.     –(–361) + 428 + 838 + 612

C.     –361 + 428 + 838 – 612

D.     –(–361) + 428 + 838 – 612

Deduce the Lewis (electron dot) structure and molecular geometry and the bond angles of PCl₃.

Comment on the value of ΔG when the reaction quotient equals the equilibrium constant, Q = K.

The combustion of glucose is exothermic and occurs according to the following equation:

C₆H₁₂O₆ (s) + 6O₂ (g) → 6CO₂ (g) + 6H₂O (g)

Which is correct for this reaction?

Explain the mechanism of the reaction between 2-bromo-2-methylpropane, (CH₃)₃CBr, and aqueous sodium hydroxide, NaOH (aq), using curly arrows to represent the movement of electron pairs.

The table shows the variation of standard Gibbs energy with temperature for a reversible reaction.

$∆G^{⦵}=∆H^{⦵}\mathit{-}T∆S^{⦵}$

$∆G^{⦵}=\mathit{-}RT \ln K$

What can be concluded about the reaction?

A.  Equilibrium shifts left as temperature increases.

B.  The forward reaction is more spontaneous below 300 K.

C.  Entropy is higher in the products than in the reactants.

D.  K_c decreases as temperature increases.

What would be the electrode potential, E^⦵, of the Mn²⁺(aq)|Mn (s) half-cell if Fe³⁺(aq)|Fe²⁺(aq) is used as the reference standard?

Mn²⁺ (aq) + 2e⁻ $\rightleftharpoons$ Mn (s)           E^⦵ = −1.18 V

Fe³⁺ (aq) + e⁻ $\rightleftharpoons$ Fe²⁺(aq)          E^⦵ = +0.77 V

A.  −1.95 V

B.  −0.41 V

C.  +0.41 V

D.  +1.95 V

Explain why the first ionization energy of sulfur is lower than that of phosphorus.

Propene is reacted first with hydrogen chloride to produce X which is then reacted with aqueous sodium hydroxide to give Y. Finally, Y is reacted with excess acidified potassium dichromate solution.

$$\text{C}{\text{H}}_{\text{3}}\text{CHC}{\text{H}}_{\text{2}}\stackrel{\text{HCL}}{\to }\text{X}\stackrel{\text{NaOH(aq)}}{\to }\text{Y}\stackrel{{\text{H}}^{+}/\text{C}{\text{r}}_2{{\text{O}}_7}^{2-}\text{(aq)}}{\to }\text{Z}$$

What is the major product, Z? 

A.     CH₃CH(OH)CH₃

B.     CH₃COCH₃

C.     CH₃CH₂CHO

D.     CH₃(CH₂)₂COOH

Which overlap of atomic orbitals leads to the formation of only a sigma (σ) bond?

       I.     s − p

       II.     p − p

       III.     s − s

A.     I and II only

B.     I and III only

C.     II and III only

D.     I, II and III

Describe how sigma (σ) and pi ($\pi$) bonds are formed.

Two cells undergoing electrolysis are connected in series.

If $x$ g of silver are deposited in cell 1, what volume of oxygen, in dm³ at STP, is given off in cell 2?

A_r(Ag) = 108; Molar volume of an ideal gas at STP = 22.7 dm³ mol⁻¹

A.    $\frac{x}{108}\times \frac{1}{4}\times 22.7$

B.    $\frac{x}{108}\times 4\times 22.7$

C.    $\frac{x}{108}\times \frac{1}{2}\times 22.7$

D.    $\frac{x}{108}\times 2\times 22.7$

Outline why TMS (tetramethylsilane) may be added to the sample to carry out ¹H NMR spectroscopy and why it is particularly suited to this role.

Outline why the rate of reaction of the similar bromo-compounds is faster.

Sketch the wedge and dash (3-D) representations of alanine enantiomers.

The rate equation for a reaction is:

rate = k[A][B]

Which mechanism is consistent with this rate equation?

A.  2A $\rightleftharpoons$ I       Fast
     I + B → P    Slow

B.  A + B $\rightleftharpoons$ I   Fast
     I + A → P    Slow

C.  A → I          Slow
     I + B → P    Fast

D.  B $\rightleftharpoons$ I         Fast
     I + A → P    Slow

Determine the pH of a 0.250 mol dm⁻³ aqueous solution of ethylamine at 298 K, using section 21 of the data booklet.

Which E^⦵ value, in V, for the reaction Mn (s) + Zn²⁺(aq) → Mn²⁺(aq) + Zn (s) can be deduced from the following equations?

Mn (s) + 2Ag⁺(aq) → Mn²⁺(aq) + 2Ag (s)     E^⦵ = 1.98 V

Zn (s) + Cu²⁺(aq) → Zn²⁺(aq) + Cu (s)        E^⦵ = 1.10 V

Cu (s) + 2Ag⁺(aq) → Cu²⁺(aq) + 2Ag (s)      E^⦵ = 0.46 V

A.  0.42

B.  1.34

C.  2.62

D.  3.54

Calculate the value of the equilibrium constant, K, at 298 K. Use sections 1 and 2 of the data booklet.

The reaction is first order with respect to HCl. Calculate the time taken, in seconds (s), for half of the Mg to dissolve when [HCl] = 0.5 mol dm^–3.

Calculate the pH of a 1.00 × 10⁻² mol dm⁻³ aqueous solution of ammonia.

pK_b = 4.75 at 298 K.

At 298 K the concentration of aqueous carbon dioxide in carbonated water is 0.200 mol dm⁻³ and the pK_a for Equilibrium (2) is 6.36.

Calculate the pH of carbonated water.

Outline why the major product, C₆H₅–CHBr–CH₃, can exist in two forms and state the relationship between these forms.

Two forms: 

Relationship:

Predict, giving a reason, whether the reduction of ReO₄⁻ to [Re(OH)₂]²⁺ would oxidize Fe²⁺ to Fe³⁺ in aqueous solution. Use section 24 of the data booklet.

Label with an asterisk, *, the chiral carbon atom.

The minor product, C₆H₅–CH₂–CH₂Br, can be directly converted to an intermediate compound, X, which can then be directly converted to the acid C₆H₅–CH₂–COOH.

C₆H₅–CH₂–CH₂Br → X → C₆H₅–CH₂–COOH

Identify X.

Which is not a requirement of the standard hydrogen electrode (SHE)?

A. V = 1 dm³

B. p(H₂) = 100 kPa

C. use of platinum as the electrode material

D. [H₃O⁺] = 1 mol dm⁻³

Consider the following table of standard electrode potentials.

Which is the strongest oxidizing agent?

A. Pb²⁺

B. Pb

C. Al³⁺

D. Al

What is the intercept on the y-axis when a graph of lnk is plotted against $\frac{1}{T}$ on the x-axis?

$\ln k=-\frac{E_a}{RT}+\ln A$

A.  lnA

B.  $-\frac{E_{\mathrm{a}}}{R}$

C.  $-\frac{R}{E_{\mathrm{a}}}$

D.   $E_{\mathrm{a}}$

Calculate the pH of 0.0100 mol dm^–3 methanoic acid stating any assumption you make. K_a = 1.6 × 10^–4.

(i) Explain the convergence of lines in a hydrogen emission spectrum.

(ii) State what can be determined from the frequency of the convergence limit.

A magnesium half-cell, Mg(s)/Mg²⁺(aq), can be connected to a copper half-cell, Cu(s)/Cu²⁺(aq).

(i) Formulate an equation for the spontaneous reaction that occurs when the circuit is completed.

(ii) Determine the standard cell potential, in V, for the cell. Refer to section 24 of the data booklet.

(iii) Predict, giving a reason, the change in cell potential when the concentration of copper ions increases.

Which reaction becomes more spontaneous as temperature increases?

A.  ${\mathrm{CaCO}}_3 \left(\mathrm{s}\right)\to \mathrm{CaO} \left(\mathrm{s}\right)+{\mathrm{CO}}_2 \left(\mathrm{g}\right)$

B.  ${\mathrm{N}}_2 \left(\mathrm{g}\right)+3{\mathrm{H}}_2 \left(\mathrm{g}\right)\rightleftharpoons 2{\mathrm{NH}}_3 \left(\mathrm{g}\right)$

C.  $3{\mathrm{CO}}_2 \left(\mathrm{g}\right)+4{\mathrm{H}}_2\mathrm{O} \left(\mathrm{g}\right)\to {\mathrm{C}}_3{\mathrm{H}}_8 \left(\mathrm{g}\right)+5{\mathrm{O}}_2 \left(\mathrm{g}\right)$

D.  ${\mathrm{SO}}_2 \left(\mathrm{g}\right)+{\mathrm{H}}_2{\mathrm{O}}_2 \left(\mathrm{l}\right)\to {\mathrm{H}}_2{\mathrm{SO}}_4 \left(\mathrm{l}\right)$

Propanone can be synthesized in two steps from propene.

Suggest why propanal is a minor product obtained from the synthetic route in (g)(i).

Which equation represents enthalpy of hydration?

A.     Na(g) → Na⁺(aq) + e⁻

B.     Na⁺(g) → Na⁺(aq)

C.     NaCl(s) → Na⁺(g) + Cl⁻(g)

D.     NaCl(s) → Na⁺(aq) + Cl⁻(aq)

Identify, from the table, a non-vanadium species that could convert ${\text{VO}}_2^{+}\text{(aq)}$ to V²⁺(aq).

The nickel obtained from another ore, nickeliferous limonite, is contaminated with iron. Both nickel and iron react with carbon monoxide gas to form gaseous complexes, tetracarbonylnickel, $\text{Ni(CO}{\text{)}}_{\text{4}}\text{(g)}$, and pentacarbonyliron, $\text{Fe(CO}{\text{)}}_{\text{5}}\text{(g)}$. Suggest why the nickel can be separated from the iron successfully using carbon monoxide.

Hydrazine reacts with water in a similar way to ammonia. (The association of a molecule of hydrazine with a second H⁺ is so small it can be neglected.)

$${\text{N}}_{\text{2}}{\text{H}}_{\text{4}}\text{(aq)}+{\text{H}}_{\text{2}}\text{O(l)}\rightleftharpoons {\text{N}}_{\text{2}}{\text{H}}_{\text{5}}^{+}\text{(aq)}+\text{O}{\text{H}}^{-}\text{(aq)}$$

$$\text{p}{K}_{\text{b}}\text{ (hydrazine)}=5.77$$

Calculate the pH of a $0.0100\text{ mol}\text{d}{\text{m}}^{-3}$ solution of hydrazine.

Discuss the bonding in the resonance structures of ozone.

Deduce one resonance structure of ozone and the corresponding formal charges on each oxygen atom.

State the rate expression for the reaction.

The standard enthalpy change, ΔH ^θ, for the hydrogenation of propene is –124.4 kJ mol^–1. Predict the temperature above which the hydrogenation reaction is not spontaneous.

Calculate the standard entropy change for this reaction using the following data.

Which equation represents the lattice enthalpy of magnesium sulfide?

A. MgS (s) → Mg (g) + S (g)

B. MgS (s) → Mg⁺ (g) + S^– (g)

C. MgS (s) → Mg²⁺ (g) + S^2– (g)

D. MgS (s) → Mg (s) + S (s)

State the reagents used in the nitration of benzene.

Sketch the general shape of the variation of pH when 50 cm³ of 0.001 mol dm^–3 NaOH (aq) is gradually added to 25 cm³ of 0.001 mol dm^–3 CH₃CH₂COOH (aq).

Calculate the change in entropy, ΔS, in J K⁻¹, for the decomposition of calcium carbonate.

Determine the value and unit of the rate constant using the rate expression in (a).

Describe the bond formation when urea acts as a ligand in a transition metal complex ion.

Which value represents the lattice enthalpy, in kJ mol⁻¹, of strontium chloride, SrCl₂?

A.     – (–829) + 164 + 243 + 550 + 1064 – (–698)

B.     –829 + 164 + 243 + 550 + 1064 – 698

C.     – (–829) + 164 + 243 + 550 + 1064 – 698

D.     –829 + 164 + 243 + 550 + 1064 – (–698)

Explain, using appropriate equations, how a suitably concentrated solution formed by the partial neutralization of 2,2-dimethylpropanoic acid with sodium hydroxide acts as a buffer solution.

Hydrogen spectral data give the frequency of 3.28 × 10¹⁵ s⁻¹ for its convergence limit.

Calculate the ionization energy, in J, for a single atom of hydrogen using sections 1 and 2 of the data booklet.

Absorption of UV light in the ozone layer causes the dissociation of oxygen and ozone.

Identify, in terms of bonding, the molecule that requires a longer wavelength to dissociate.

Deduce the gas formed at the anode (positive electrode) when graphite is used in place of copper.

Deduce, giving a reason, the more likely structure.

Nitrobenzene, C₆H₅NO₂, can be converted to phenylamine via a two-stage reaction.

In the first stage, nitrobenzene is reduced with tin in an acidic solution to form an intermediate ion and tin(II) ions. In the second stage, the intermediate ion is converted to phenylamine in the presence of hydroxide ions.

Formulate the equation for each stage of the reaction.

Sodium emits yellow light with a frequency of 5.09 × 10¹⁴Hz when electrons transition from 3p to 3s orbitals.

Calculate the energy difference, in J, between these two orbitals using sections 1 and 2 of the data booklet.

Darling, D, n.d. D lines (of sodium). [online] Available at <https://www.daviddarling.info/encyclopedia/D/D_lines.html> [Accessed 6 May 2020].

Calculate the Gibbs free energy change (ΔG), in kJ mol⁻¹, for this reaction at 25 °C. Use section 1 of the data booklet.

If you did not obtain an answer in c(i) or c(ii) use −87.6 kJ mol⁻¹ and −150.5 J mol⁻¹K⁻¹ respectively, but these are not the correct answers.

Deduce the product of the complete reduction reaction in (e)(i).

How many chiral carbon atoms are present in one molecule of (CH₃)₂CHCHClCHBrCH₃?

A.   0

B.   1

C.   2

D.   3

Calculate the standard Gibbs free energy change, ΔG^Θ, in kJ, for this reaction at 1000 K. Use sections 1 and 2 of the data booklet.

What is the activation energy according to the following plot of the linear form of the Arrhenius equation?

Arrhenius equation: $k=A{e}^{\frac{\mathit{-}Ea}{RT}}$.

A.  $E_a=\frac{2\times 8.31}{0.06}$

B.  $E_a=\frac{-2\times 8.31}{0.06}$

C.  $E_a=e^{\frac{2\times 8.31}{0.06}}$

D.  $E_a=e^{\frac{-2\times 8.31}{0.06}}$

What is the formal charge of the oxygen atom in H₃O⁺?

A.  −2

B.  −1

C.  0

D.  +1

[Cr(OH₂)₆]³⁺ is violet and [Cr(NH₃)₆]³⁺ is yellow. What is correct?

The Colour Wheel

Explain the mechanism of the reaction using curly arrows to represent the movement of electron pairs.

Deduce the splitting pattern in the ¹H NMR spectrum for 1-bromopropane.

Write the equation for the production of the active nitrating agent from concentrated sulfuric and nitric acids.

The standard enthalpy of formation of sodium oxide is −414 kJ mol⁻¹. Determine the lattice enthalpy of sodium oxide, in kJ mol⁻¹, using section 8 of the data booklet and your answers to (d)(i).

(If you did not get answers to (d)(i), use +850 kJ mol⁻¹ and +600 kJ mol⁻¹ respectively, but these are not the correct answers.)

Explain, using two equations, how an equimolar solution of ammonia and ammonium ions acts as a buffer solution when small amounts of acid or base are added.

It has been suggested that the reaction occurs as a two-step process:

Step 1: N₂O (g) → N₂ (g) + O (g)

Step 2: N₂O (g) + O (g) → N₂ (g) + O₂ (g)

Explain how this could support the observed rate expression.

Identify the colour of the emission spectrum of lithium using section 17 of the data booklet.

Which has the strongest conjugate base?

A. HCOOH (K_a = 1.8 × 10⁻⁴)

B. HNO₂ (K_a = 7.2 × 10⁻⁴)

C. HCN (K_a = 6.2 × 10⁻¹⁰)

D. HIO₃ (K_a = 1.7 × 10⁻¹)

Where is the buffer region for the titration of a weak acid with a strong base?

Predict, giving a reason, the effect of increasing temperature on the stability of copper(I) chloride solution.

Which can show optical activity?

A.  CHBrCHCl

B.  CH₃CH₂CHBrCH₂CH₃

C.  (CH₃)₂CBrCl

D.  CH₃CH₂CH(CH₃)Br

In which compound is the halogen substituted the most rapidly by aqueous hydroxide ions?

A. (CH₃)₃CCl

B. (CH₃)₃CI

C. CH₃CH₂CH₂CH₂Cl

D. CH₃CH₂CH₂CH₂I

Decomposition of hydrogen peroxide in an aqueous solution proceeds as follows.

2H₂O₂(aq) → 2H₂O(l) + O₂(g)

The rate expression for the reaction was found to be: rate = k [H₂O₂].

Which graph is consistent with the given rate expression?

Which species is a Lewis acid but not a Brønsted–Lowry acid?

A.  ${\mathrm{Cu}}^{2+}$

B.  ${{\mathrm{NH}}_4}^{+}$

C.  $\mathrm{Cu}$

D.  ${\mathrm{CH}}_3\mathrm{COOH}$

Calculate the standard Gibbs free energy change, $∆G^{⦵}$, in $\mathbf{kJ}\mathbf{ }{\mathbf{mol}}^{\mathbf{–}\mathbf{1}}$, for the reaction (A to B) at $298 \mathrm{K}$. Use sections 1 and 2 of the data booklet.

Calculate $∆S^{⦵}$ for the reaction in $\mathrm{J} {\mathrm{K}}^{-1}$, using section 12 of the data booklet.

The standard molar entropy for oxygen gas is $205 \mathrm{J} {\mathrm{K}}^{-1} {\mathrm{mol}}^{-1}$.

Write the balanced equation for the reaction in this voltaic cell.

A buffer is produced by mixing 20.0 cm³ of 0.10 mol dm⁻³ ethanoic acid, CH₃COOH(aq), with 0.10 mol dm⁻³ sodium hydroxide, NaOH(aq).

What is the volume of NaOH required and the pH of the buffer?

In the electrolysis of aqueous potassium nitrate, KNO₃(aq), using inert electrodes, 0.1 mol of a gas was formed at the cathode (negative electrode).

Which is correct?

Calculate the standard entropy change, $\mathrm{\Delta }{S}^{\theta }$, of the reaction, in $\text{J}{\text{K}}^{-1}$, using the values given.

When the product X is reacted with NaOH in a hot alcoholic solution, C₂H₃Cl is formed. State the role of the reactant NaOH other than as a nucleophile.

State the reagents used to convert benzene to nitrobenzene and the formula of the electrophile formed.

At a given time, the concentration of NO₂(g) and N₂O₄(g) were 0.52 and $0.10\text{ mol}\text{d}{\text{m}}^{-3}$ respectively.

Deduce, showing your reasoning, if the forward or the reverse reaction is favoured at this time.

Suggest the structural formula of this compound.

Predict the chemical shift and the splitting pattern seen for the hydrogens on the carbon atom circled in the diagram. Use section 27 of the data booklet.

Calculate the cell potential, in V, when the standard iodine and manganese half-cells are connected.

What are the products when an aqueous solution of copper(II) sulfate is electrolysed using inert graphite electrodes?

Determine the value of ΔG^θ, in kJ, for the above reaction at 761 K using section 1 of the data booklet.

Which compound produces the following ¹H NMR spectrum?

SDBS, National Institute of Advanced Industrial Science and Technology (AIST).

A.  Propane

B.  Propanone

C.  Propanal

D.  2,2-dimethylpropane

Which change results in the largest negative value of ΔS?

A.  C₂H₅OH (l) + SOCl₂(l) → C₂H₅Cl (l) + SO₂(g) + HCl (g)

B.  CaCO₃(s) → CaO (s) + CO₂(g)

C.  H₂O (l) → H₂O (s)

D.  NH₃(g) + HCl (g) → NH₄Cl (s)

A voltaic cell is set up between the Fe²⁺(aq) | Fe (s) and Fe³⁺ (aq) | Fe²⁺ (aq) half-cells.

Deduce the equation and the cell potential of the spontaneous reaction. Use section 24 of the data booklet.

Determine the concentration of methanoic acid in a solution of pH = 4.12. Use section 21 of the data booklet.

Identify if aqueous solutions of the following salts are acidic, basic, or neutral.

Determine an approximate order of magnitude for K_c, using sections 1 and 2 of the data booklet. Assume ΔG^Θ for the forward reaction is approximately +50 kJ at 298 K.

Deduce the number of σ and $\pi$ bonds in a molecule of ethyne.

Calculate the standard free energy change, ΔG^Θ, in kJ, for the reaction at 298 K using your answer to (b)(ii).

Suggest how this product could be synthesized in one step from butanoic acid.

The graph represents the titration of 25.00 cm³ of 0.100 mol dm⁻³ aqueous ethanoic acid with 0.100 mol dm⁻³ aqueous sodium hydroxide.

Deduce the major species, other than water and sodium ions, present at points A and B during the titration.

The rate constant for a reaction doubles when the temperature is increased from 25.0 °C to 35 °C.

Calculate the activation energy, E_a, in kJ mol⁻¹ for the reaction using section 1 and 2 of the data booklet.

Mass spectra A and B of the two isomers are given.

Explain which spectrum is produced by each compound using section 28 of the data booklet.

State the type of solvent most suitable for the reaction.

Consider the Born–Haber cycle for the formation of sodium oxide:

What is the lattice enthalpy, in kJ mol⁻¹, of sodium oxide?

A.  414 + 2(108) + 249 + 2(496) − 141 + 790

B.  414 + 2(108) + 249 + 2(496) + 141 + 790

C.  −414 + 2(108) + 249 + 2(496) − 141 + 790

D.  −414 − 2(108) − 249 − 2(496) + 141 − 790

The graph shows the first six ionization energies of an element.

Why is hydrated copper (II) sulfate blue?

A.  Blue light is emitted when electrons return to lower d-orbitals.

B.  Light complimentary to blue is absorbed when electrons return to lower d-orbitals.

C.  Blue light is emitted when electrons are promoted between d-orbitals.

D.  Light complimentary to blue is absorbed when electrons are promoted between d-orbitals.

Calculate the free energy change, ΔG^⦵, in kJ, of the cell reaction. Use sections 1 and 2 of the data booklet.

Determine, giving a reason, if iodine will also oxidize iron(II). 

Sketch the shape of one sigma ($\text{σ}$) and one pi ($\mathrm{\pi }$) bond.

State the reagent used to convert benzoic acid to phenylmethanol (benzyl alcohol), C₆H₅CH₂OH.

Deduce how the rate of reaction at t = 2 would compare to the initial rate.

Aqueous sodium hydrogencarbonate has a pH of approximately 7 at 298 K.

Sketch a graph of pH against volume when 25.0cm³ of 0.100 mol dm⁻³ NaOH (aq) is gradually added to 10.0cm³ of 0.0500 mol dm⁻³ NaHCO₃ (aq).

Which class of compound is formed when a ketone is reduced?

A. primary alcohol

B. secondary alcohol

C. ether

D. carboxylic acid

Determine, showing your working, the wavelength, in m, of ultraviolet light absorbed by a single molecule in one of these steps. Use sections 1, 2 and 11 of the data booklet.

Calculate the standard Gibbs free energy change, ΔG^θ, to two significant figures, for the disproportionation at 298 K. Use your answer from (e)(i) and sections 1 and 2 of the data booklet.

Comment on the spontaneity of the reaction at 298 K.

Determine the enthalpy of solution of copper(II) chloride, using data from sections 18 and 20 of the data booklet.

The enthalpy of hydration of the copper(II) ion is −2161 kJ mol⁻¹.

Which mixture is a buffer solution?

A.  25 cm³ of 0.10 mol dm^-3 NH₃ (aq) and 50 cm³ of 0.10 mol dm^-3 HCl (aq)

B.  50 cm³ of 0.10 mol dm^-3 NH₃ (aq) and 25 cm³ of 0.10 mol dm^-3 HCl (aq)

C.  25 cm³ of 0.10 mol dm^-3 NaOH (aq) and 25 cm³ of 0.10 mol dm^-3 HCl (aq)

D.  50 cm³ of 0.10 mol dm^-3 NaOH (aq) and 25 cm³ of 0.10 mol dm^-3 HCl (aq)

Which property explains why tetramethylsilane, Si(CH₃)₄, can be used as a reference standard in ¹H NMR spectroscopy?

A. It has a high boiling point.

B. It is a reactive compound.

C. All its protons are in the same chemical environment.

D. It gives multiple signals.

A mixture of 0.40 mol of CO (g) and 0.40 mol of H₂ (g) was placed in a 1.00 dm³ vessel. The following equilibrium was established.

CO (g) + 2H₂ (g)  CH₃OH (g)

At equilibrium, the mixture contained 0.25 mol of CO (g). How many moles of H₂ (g) and CH₃OH (g) were present at equilibrium?

Which graph represents the relationship between the rate constant, $k$, and temperature, $T$, in kelvin?

The electron configuration of copper makes it a useful metal.

Copper plating can be used to improve the conductivity of an object.

State, giving your reason, at which electrode the object being electroplated should be placed.

Suggest, giving a reason, which point on the curve is considered a buffer region.

Calculate the $K_{\mathrm{b}}$ of the conjugate base of ethanoic acid using sections 2 and 21 of the data booklet.

Which statement explains one of the decreases in first ionization energy (I.E.) across period 3?

A.     The nuclear charge of element Al is greater than element Mg.

B.     The electron-electron repulsion is greater, for the electron with the opposite spin, in element S than in element P.

C.     A new sub-level is being filled at element S.

D.     The p orbital being filled in element Al is at a lower energy than the s orbital in element Mg.

Which statement is correct for the overall reaction in a voltaic cell?

2AgNO₃(aq) + Ni(s) → 2Ag(s) + Ni(NO₃)₂(aq)         E ^θ= +1.06 V

A.     Electrons flow from Ag electrode to Ni electrode.

B.     Ni is oxidized to Ni²⁺ at the cathode (negative electrode).

C.     Ag⁺ is reduced to Ag at the anode (positive electrode).

D.     Ag has a more positive standard electrode potential value than Ni.

Suggest why experiments involving tetracarbonylnickel are very hazardous.

State the electron domain geometry around the nitrogen atom and its hybridization in methanamine.

Formulate two equations to show how nitrogen(II) oxide, NO, catalyses the destruction of ozone.

A mixture of enantiomers shows optical rotation.

Suggest a conclusion you can draw from this data.

Sketch the relationship between the rate of reaction and the concentration of NO₂.

State the reagents and the name of the mechanism for the nitration of benzene.

Below are two isomers, A and B, with the molecular formula C₄H₉Br.

Explain the mechanism of the nucleophilic substitution reaction with NaOH(aq) for the isomer that reacts almost exclusively by an S_N2 mechanism using curly arrows to represent the movement of electron pairs.

State the rate expression for the reaction.

Sketch the mechanism for the reaction of propene with hydrogen bromide using curly arrows.

Calculate the pH of 0.00100 mol dm^–3 propanoic acid solution. Use section 21 of the data booklet.

Deduce, giving a reason, which complex ion [Cr(CN)₆]³⁻ or [Cr(OH)₆]³⁻ absorbs higher energy light. Use section 15 of the data booklet.

Calculate the Gibbs free energy change, ΔG^⦵, in kJ, for the cell, using section 1 of the data booklet.

Draw diagrams to show how sigma (σ) and pi (π) bonds are formed between atoms.

Determine the temperature, in K, above which the reaction becomes spontaneous.

Which system has the most negative entropy change, ΔS, for the forward reaction?

A.     N₂(g) + 3H₂(g) $\rightleftharpoons$ 2NH₃(g)

B.     CaCO₃(s) → CaO(s) + CO₂(g)

C.     2S₂O₃²⁻(aq) + I₂(aq) → S₄O₆²⁻(aq) + 2I^–(aq)

D.     H₂O(l) → H₂O(g)

Compare and contrast the mechanisms by which 1-chlorobutane, CH₃CH₂CH₂CH₂Cl, and 2-chloro-2-methylpropane, (CH₃)₃CCl, react with aqueous sodium hydroxide, giving two similarities and one difference.

Calculate the standard electrode potential, in V, for the BrO₃⁻/Br⁻ reduction half‑equation using section 24 of the data booklet.

Carbon dioxide can be represented by at least two resonance structures, I and II.

Calculate the formal charge on each oxygen atom in the two structures.

Consider the following standard electrode potentials:

Which species will react with each other spontaneously under standard conditions?

A.  Zn²⁺(aq) + Pb (s)

B.  Pb²⁺(aq) + Br₂(l)

C.  Zn (s) + Br⁻(aq)

D.  Pb (s) + Br₂ (l)

Which aqueous solutions produce oxygen gas during electrolysis?

I.   Dilute CuCl₂(aq) with inert electrodes
II.  Dilute FeSO₄(aq) with inert electrodes
III. Dilute CuCl₂(aq) with copper electrodes

The standard electrode potentials are provided in the table:

A.  I and II only

B.  I and III only

C.  II and III only

D.  I, II and III

Determine the initial rate of reaction in experiment 4.

Which change is exothermic?

A.  $\frac{1}{2}$Cl₂ (g) → Cl (g)

B.   K (g) → K⁺ (g) + e⁻

C.   KCl (s) → K⁺ (g) + Cl⁻ (g)

D.   Cl (g) + e⁻ → Cl⁻ (g)

An indicator, HIn, has a pK_a of 5.1.

HIn (aq) $\rightleftharpoons$ H⁺ (aq) + In⁻ (aq)

colour A                      colour B

Which statement is correct?

A.   At pH = 7, colour B would be observed
B.   At pH = 3, colour B would be observed
C.   At pH = 7, [HIn] = [In⁻]
D.   At pH = 3, [HIn] < [In⁻]

Which is correct for the complex ion in [Fe(H₂O)₅Cl]SO₄?

Calculate the value of the rate constant stating its units.

Deduce the order of reaction with respect to hydrogen.

Draw the full structural formula of (Z)-but-2-ene.

Predict, giving a reason, the major product of reaction between but-1-ene and steam.

Sketch a graph of pH against volume of hydrochloric acid added to ammonia solution, showing how you would determine the pK_a of the ammonium ion.

State the hybridization of the nitrogen atom in chloramine.

Calculate ΔG^θ, in kJ, for the spontaneous reaction in (f)(i), using sections 1 and 2 of the data booklet.

Dinitrogen monoxide has a positive standard enthalpy of formation, ΔH_f^θ.

Deduce, giving reasons, whether altering the temperature would change the spontaneity of the decomposition reaction.

Deduce the splitting pattern you would expect for the signals in a high resolution ¹H NMR spectrum.

2.3 ppm:

9.8 ppm:

Determine the standard entropy change, in J K−1, for the decomposition of dinitrogen monoxide.

2N₂O (g) → 2N₂ (g) + O₂ (g)

Which equation represents lattice enthalpy?

A. NaCl (g) → Na⁺ (g) + Cl⁻ (g)

B. NaCl (s) → Na⁺ (g) + Cl⁻ (g)

C. NaCl (s) → Na⁺ (aq) + Cl⁻ (aq)

D. NaCl (s) → Na⁺ (s) + Cl⁻ (s)

Which change has the greatest increase in entropy?

A. CO₂ (s) → CO₂ (g)

B. CO₂ (g) → CO₂ (l)

C. CO₂ (g) → CO₂ (s)

D. CO₂ (l) → CO₂ (s)

How many sigma (σ) and pi (π) bonds are present in hydrogen cyanide, HCN?

Describe how the blue colour is produced in the Cu(II) solution. Refer to section 17 of the data booklet.

Sketch the mechanism using curly arrows to represent the movement of electrons.

Suggest, giving a reason, whether the entropy of the system increases or decreases during the disproportionation.

Which reaction has the greatest increase in entropy of the system?

A. HCl (g) + NH₃ (g) → NH₄Cl (s)

B. (NH₄)₂Cr₂O₇ (s) → Cr₂O₃ (s) + N₂ (g) + 4H₂O (g)

C. CaCO₃ (s) → CaO (s) + CO₂ (g)

D. I₂ (g) → I₂ (s)

Which salt solution has the highest pH?

A. NH₄Cl

B. Ca(NO₃)₂

C. Na₂CO₃

D. K₂SO₄

Construct the mechanism of the formation of 2-bromopropane from hydrogen bromide and propene using curly arrows to denote the movement of electrons.

Which molecule has an enantiomer?

A.  ${\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{CH}\left(\mathrm{OH}\right){\mathrm{CH}}_2{\mathrm{CH}}_3$

B.  ${\mathrm{CH}}_2\left(\mathrm{OH}\right){\mathrm{CH}}_2{\mathrm{CH}}_2\mathrm{CH}={\mathrm{CH}}_2$

C.  ${\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{CH}}_2\mathrm{CH}=\mathrm{CHBr}$

D.  ${\mathrm{CH}}_3{\mathrm{CHBrCH}}_2{\mathrm{CH}}_2{\mathrm{CH}}_3$

State the number of sigma ($\mathrm{\sigma }$) and pi ($\mathrm{\pi }$) bonds around the central carbon atom in molecule B.

$\mathrm{CFC}$s produce chlorine radicals. Write two successive propagation steps to show how chlorine radicals catalyse the depletion of ozone.

Deduce the number of signals and chemical shifts with splitting patterns in the ¹H NMR spectrum of ethoxyethane. Use section 27 of the data booklet.

Calculate the standard cell potential, in $\mathrm{V}$, for the cell at $298 \mathrm{K}$. Use section 24 of the data booklet

Calculate the standard Gibbs free energy change, $∆{\mathrm{G}}^{⦵}$, in $\mathbf{kJ}$, for the reaction at 5 °C, using your answers to (b) and (d). Use section 1 of the data booklet.

(If you did not obtain an answer to (b) or (d) use values of $-1952 \mathrm{kJ}$ and $+113 \mathrm{J} {\mathrm{K}}^{-1}$ respectively, although these are not the correct answers.)

The electron configuration of copper makes it a useful metal.

Determine the frequency of a photon that will cause the first ionization of copper. Use sections 1, 2 and 8 of the data booklet.

The electron configuration of copper makes it a useful metal.

Explain why a copper(II) solution is blue, using section 17 of the data booklet.

Which technique is used to determine the bond lengths and bond angles of a molecule?

A.     X-ray crystallography

B.     Infrared (IR) spectroscopy

C.     Mass spectroscopy

D.     ¹H NMR spectroscopy

Explain why tetramethylsilane (TMS) is often used as a reference standard in ¹H NMR.

Ammonia is a stronger ligand than water. Which is correct when concentrated aqueous ammonia solution is added to dilute aqueous copper(II) sulfate solution?

A.     The d-orbitals in the copper ion split.

B.     There is a smaller splitting of the d-orbitals.

C.     Ammonia replaces water as a ligand.

D.     The colour of the solution fades.

Components X and Y are mixed together and allowed to reach equilibrium. The concentrations of X, Y, W and Z in the equilibrium mixture are 4, 1, 4 and $\text{2 mol}\text{d}{\text{m}}^{-3}$ respectively.

X + 2Y $\rightleftharpoons$ 2W + Z

What is the value of the equilibrium constant, K_c?

A.     $\frac{1}{8}$

B.     $\frac{1}{2}$

C.     2

D.     8

The first six ionization energies, in kJ mol^–1, of an element are given below.

Explain the large increase in ionization energy from IE₃ to IE₄.

Outline, in terms of the bonding present, why the reaction conditions of halogenation are different for alkanes and benzene.

The following curve was obtained using a pH probe.

State, giving a reason, the strength of the acid.

Hydrogenation of propene produces propane. Calculate the standard entropy change, ΔS^θ, for the hydrogenation of propene.

Ammonia reacts reversibly with water.
$$\text{N}{\text{H}}_{\text{3}}\text{(g)}+{\text{H}}_{\text{2}}\text{O(l)}\rightleftharpoons {\text{NH}}_{\text{4}}^{+}\text{(aq)}+\text{O}{\text{H}}^{-}\text{(aq)}$$
Explain the effect of adding ${\text{H}}^{+}\text{(aq)}$ ions on the position of the equilibrium.

What information can be deduced from the splitting pattern of ¹H NMR signals?

A.  total number of hydrogen atoms in a compound

B.  number of hydrogen atoms on adjacent atom(s)

C.  functional group on which hydrogen atoms are located

D.  number of hydrogen atoms in a particular chemical environment

State and explain the products of electrolysis of a concentrated aqueous solution of sodium chloride using inert electrodes. Your answer should include half-equations for the reaction at each electrode.

The rate expression for the reaction X (g) + 2Y (g) → 3Z (g) is 

rate = k[X]⁰ [Y]²

By which factor will the rate of reaction increase when the concentrations of X and Y are both increased by a factor of 3?

A. 6

B. 9

C. 18

D. 27

What is the standard enthalpy of formation, in kJ mol^–1, of IF (g)?

IF₇ (g) + I₂ (s) → IF₅ (g) + 2IF (g)        ΔH${}^{\theta }$ = –89 kJ

ΔH${}_f^{\theta }$ (IF₇) = –941 kJ mol^–1

ΔH${}_f^{\theta }$ (IF₅) = –840 kJ mol^–1

A. –190

B. –95

C. +6

D. +95

Calculate [H₃O⁺] in the solution and the dissociation constant, K_a , of the acid at 25 °C.

Which substance has the highest lattice enthalpy?

A.  $\text{KCl}$

B.  ${\text{CaCl}}_2$

C.  $\text{KF}$

D.  ${\text{CaF}}_{\text{2}}$

What are the products when concentrated aqueous copper (II) chloride is electrolysed using platinum electrodes?

Calculate a value for the entropy change, ΔS^⦵, in J K^–1 mol^–1 at 298 K. Use your answers to (e)(i) and section 1 of the data booklet.

If you did not get answers to (e)(i) use –1 kJ, but this is not the correct answer.

Calculate the value of the rate constant, k, giving its units.

Write the rate expression for this reaction.

Determine the temperature, in K, at which the decomposition of calcium carbonate becomes spontaneous, using b(i), b(ii) and section 1 of the data booklet.

(If you do not have answers for b(i) and b(ii), use ΔH = 190 kJ and ΔS = 180 J K⁻¹, but these are not the correct answers.)

What are the major products of electrolysing concentrated aqueous potassium iodide, KI(aq)?

Calculate the rate constant of the reaction, stating its units.

Determine the pH of 0.010 mol dm⁻³ 2,2-dimethylpropanoic acid solution.

K_a (2,2-dimethylpropanoic acid) = 9.333 × 10⁻⁶

Calculate the cell potential, in V, using section 24 of the data booklet.

Determine the loss in mass of one electrode if the mass of the other electrode increases by 0.10 g.

The table lists standard entropy, S^Θ, values.

Calculate the standard entropy change for the reaction, ΔS^Θ, in J K⁻¹.

CH₄(g) + H₂O(g) → 3H₂(g) + CO(g)

Which product is formed when CH₃COCH₂CH₃ is reduced with sodium borohydride?

A.  CH₃CH₂CH₂CHO

B.  CH₃CH₂CH₂CH₂OH

C.  CH₃CH(OH)CH₂CH₃

D.  CH₃CH₂CH₂COOH

Copper is a transition metal that forms different coloured complexes. A complex [Cu(H₂O)₆]²⁺(aq) changes colour when excess Cl⁻(aq) is added.

Explain the cause of this colour change, using sections 3 and 15 from the data booklet.

Sketch the neutralisation curve obtained and label the equivalence point.

Distinguish between a sigma and pi bond.

Consider the standard electrode potentials:

Cr³⁺ (aq) + 3e⁻ $\rightleftharpoons$ Cr (s)       E^Θ = −0.74 V

Hg²⁺ (aq) + 2e⁻ $\rightleftharpoons$ Hg (l)      E^Θ = +0.85 V

What is the cell potential, in V, for the voltaic cell?

2Cr (s) + 3Hg²⁺ (aq) → 3Hg (l) + 2Cr³⁺ (aq)

A.   −1.59

B.   +0.11

C.   +1.07

D.   +1.59

State and explain the magnetic property of iron(II) and iron(III) ions.

Predict, giving your reasons, whether the forward reaction is endothermic or exothermic. Use your answers to (b) and (c).

Draw two Lewis (electron dot) structures for BrO₃⁻.

Copper(II) ion solutions are blue. Suggest, giving your reason, a suitable wavelength of light for the analysis.

In which reaction does entropy decrease?

A.  NaCl (s) → NaCl (aq)

B.  Zn (s) + H₂SO₄(aq) → ZnSO₄(aq) + H₂(g)

C.  NH₃(g) + HCl (g) → NH₄Cl (s)

D.  CuCO₃(s) → CuO (s) + CO₂(g)

Use the graph to deduce the dependence of the reaction rate on the amount of Mg.

Magnesium salts form slightly acidic solutions owing to equilibria such as:

Mg²⁺(aq) + H₂O (l) $\rightleftharpoons$ Mg(OH)⁺(aq) + H⁺(aq)

Comment on the role of Mg²⁺ in forming the Mg(OH)⁺ ion, in acid-base terms.

Deduce the number of signals that you would expect in the ¹H NMR spectrum of nitrobenzene and the relative areas of these.

Deduce a Lewis (electron dot) structure of the nitric acid molecule, HNO₃, that obeys the octet rule, showing any non-zero formal charges on the atoms.

Explain the relative lengths of the three bonds between N and O in nitric acid.

Deduce the rate expression for the reaction.

Predict, giving a reason, how the value of the ΔS^⦵_reaction would be affected if ${\text{I}}_2$ (g) were used as a reactant.

Explain why, when ligands bond to the iron ion causing the d-orbitals to split, the complex is coloured.

Dinitrogen monoxide in the stratosphere is converted to nitrogen monoxide, NO (g).

Write two equations to show how NO (g) catalyses the decomposition of ozone.

Deduce the hybridization of the central nitrogen atom in the molecule.

The reaction of the hydroxide ion with carbon dioxide and with the hydrogencarbonate ion can be represented by Equations 3 and 4.

Equation (3)     OH⁻ (aq) + CO₂ (g) → HCO₃⁻ (aq)
Equation (4)     OH⁻ (aq) + HCO₃⁻ (aq) → H₂O (l) + CO₃²⁻ (aq)

Discuss how these equations show the difference between a Lewis base and a Brønsted–Lowry base.

Equation (3):

Equation (4):

What is the order with respect to each reactant?

2NO (g) + Cl₂ (g) → 2NOCl (g)

Which electrons are removed from iron (Z = 26) to form iron(II)?

A. two 3d electrons

B. two 4s electrons

C. one 4s electron and one 3d electron

D. two 4p electrons

Which is a major product of the electrophilic addition of hydrogen chloride to propene?

A. ClCH₂CH=CH₂

B. CH₃CH(Cl)CH₃

C. CH₃CH₂CH₂Cl

D. CH₃CH=CHCl

What is the oxidation state of the metal ion and charge of the complex ion in [Co(NH₃)₄Cl₂]Cl?

What are the products when concentrated KBr (aq) is electrolyzed?

Write an equation for the reaction of the major product with aqueous sodium hydroxide to produce a C₃H₈O compound, showing structural formulas.

What is the order of increasing (more exothermic) enthalpy of hydration?

Xⁿ⁺ (g) → Xⁿ⁺ (aq)

A.  Ca²⁺, Mg²⁺, K⁺, Na⁺

B.  Na⁺, K⁺, Mg²⁺, Ca²⁺

C.  K⁺, Na⁺, Ca²⁺, Mg²⁺

D.  Mg²⁺, Ca²⁺, Na⁺, K⁺

Examine the relationship between the Brønsted–Lowry and Lewis definitions of a base, referring to the ligands in the complex ion [CuCl₄]²⁻.

Calculate the standard Gibbs free energy change, $\mathrm{\Delta }{G}^{\text{θ}}$, in kJ mol⁻¹, for the first dissociation of citric acid at 298 K, using section 1 of the data booklet.

When excess ammonia is added to copper(II) chloride solution, the dark blue complex ion, [Cu(NH₃)₄(H₂O)₂]²⁺, forms.

State the molecular geometry of this complex ion, and the bond angles within it.

Molecular geometry:

Bond angles: 

Deduce the half-equations for the reactions occurring at the electrodes.

Anode (negative electrode):

Cathode (positive electrode):

(i) Calculate ΔH^θ, in kJ, for this similar reaction below using $\mathrm{\Delta }{H}_{\mathrm{f}}^{\theta }$ data from section 12 of the data booklet. $\mathrm{\Delta }{H}_{\mathrm{f}}^{\theta }$ of HOCH₂CH₂OH(l) is –454.8kJmol^-1.

2CO (g) + 3H₂ (g) $\rightleftharpoons$ HOCH₂CH₂OH (l)

(ii) Deduce why the answers to (a)(iii) and (b)(i) differ.

(iii) ΔS^θ for the reaction in (b)(i) is –620.1JK^-1. Comment on the decrease in entropy.

(iv) Calculate the value of ΔG^θ, in kJ, for this reaction at 298 K using your answer to (b)(i). (If you did not obtain an answer to (b)(i), use –244.0 kJ, but this is not the correct value.)

(v) Comment on the statement that the reaction becomes less spontaneous as temperature is increased.

Magnesium chloride can be electrolysed.

(i) Deduce the half-equations for the reactions at each electrode when molten magnesium chloride is electrolysed, showing the state symbols of the products. The melting points of magnesium and magnesium chloride are 922K and 987K respectively.

(ii) Identify the type of reaction occurring at the cathode (negative electrode).

(iii) State the products when a very dilute aqueous solution of magnesium chloride is electrolysed.

The oxidation state of cobalt in the complex ion [Co(NH₃)₅Br]^x is +3. Which of the following statements are correct?

I.   The overall charge, x, of the complex ion is 2+.
II.  The complex ion is octahedral.
III. The cobalt(III) ion has a half-filled d-subshell.

A.  I and II only

B.  I and III only

C.  II and III only

D.  I, II and III

Which combination gives the standard hydration enthalpy of ${\mathrm{Na}}^{+} \left(\mathrm{g}\right)$?

A.  $4+359+790$

B.  $4+359-790$

C.  $-4-359+790$

D.  $4-359+790$

What are the units of the rate constant, $k$, if the rate equation is $\mathrm{Rate}=k\left[\mathrm{A}\right]{\left[\mathrm{B}\right]}^2$?

A.  $\mathrm{mol} {\mathrm{dm}}^{-3} {\mathrm{s}}^{-1}$

B.  ${\mathrm{dm}}^3 {\mathrm{mol}}^{-1 }{\mathrm{s}}^{-1}$

C.  ${\mathrm{dm}}^6 {\mathrm{mol}}^{-2 }{\mathrm{s}}^{-1}$

D.  ${\mathrm{dm}}^9 {\mathrm{mol}}^{-3 }{\mathrm{s}}^{-1}$

Which is the electrophile in the nitration of benzene?

A.  ${\mathrm{HNO}}_3$

B.  ${{\mathrm{NO}}_2}^{+}$

C.  ${{\mathrm{NO}}_2}^{-}$

D.  ${{\mathrm{NH}}_4}^{+}$

State the type of hybridization shown by the central carbon atom in molecule B.

Identify the major species, other than water and potassium ions, at these points.

Predict, giving a reason, whether the entropy change, $∆S^{⦵}$, for this reaction is negative or positive.

Calculate the cell potential for $0.0100 \mathrm{mol} {\mathrm{dm}}^{-3} {\mathrm{Mg}}^{2+}\left(\mathrm{aq}\right)$ and $0.800 \mathrm{mol} {\mathrm{dm}}^{-3} {\mathrm{Ni}}^{2+}\left(\mathrm{aq}\right)$ at $298 \mathrm{K}$. Use sections 1, 2 and 24 of the data booklet.

What are the units for the rate constant, k, in the expression?

Rate = k [X]²[Y]

A.     mol² dm⁻⁶ s⁻¹

B.     mol⁻¹ dm³ s⁻¹

C.     mol dm⁻³ s⁻¹

D.     mol⁻² dm⁶ s⁻¹

When the reaction is carried out in the absence of acid the following graph is obtained.

Discuss the shape of the graph between A and B.

Sketch a graph of the first six successive ionization energies of vanadium on the axes provided.

Describe, in terms of the electrons involved, how the bond between a ligand and a central metal ion is formed.

Deduce the splitting patterns in the ¹H NMR spectrum of C₂H₅Cl.

Suggest why the loss of ozone is an international environmental concern.

In which order should the reagents be used to convert benzene into phenylamine (aniline)?

Deduce the pK_a for this acid.

How many sigma (σ) and pi (π) bonds are present in this molecule?

Calculate K_b for HCO₃^– acting as a base.

State an equation for the formation of NO₂⁺.

What is the overall charge, $x$, of the chromium (III) complex?

$\left[\mathrm{Cr}\right({\mathrm{H}}_2\mathrm{O}{)}_4{\mathrm{Cl}}_2{]}^x$

A.  0

B.  1+

C.  2−

D.  3+

A reaction proceeds by the following mechanism:

step 1: $\mathrm{A}+\mathrm{A}\to \mathrm{B}$
step 2: $\mathrm{B}+\mathrm{C}\to \mathrm{D}$

Which rate equation is consistent with this mechanism?

A.  Rate = k[B]²[C]

B.  Rate = k[A]²[B][C]

C.  Rate = k[A]²

D.  Rate = k[A][C]

[Cr(OH)₆]³⁻ forms a green solution. Estimate a wavelength of light absorbed by this complex, using section 17 of the data booklet.

Determine the rate expression for the reaction.

Identify an indicator that could be used for the titration in 5(d)(i), using section 22 of the data booklet.

SO₂ (g), O₂(g) and SO₃(g) are mixed and allowed to reach equilibrium at 600 °C.

Determine the value of K_c at 600 °C.

Predict the splitting pattern of the ¹H NMR spectrum of urea.

Calculate the pH of 0.100 mol dm⁻³ aqueous ethanoic acid.

K_a = 1.74 × 10⁻⁵

Sketch a graph of the first six ionization energies of calcium.

Describe how the activation energy of this reaction could be determined.

Predict whether the pH of an aqueous solution of ammonium chloride will be greater than, equal to or less than 7 at 298 K.

A two-step mechanism is proposed for the formation of NO₂(g) from NO(g) that involves an exothermic equilibrium process.

First step: 2NO(g) $\rightleftharpoons$ N₂O₂(g)     fast

Second step: N₂O₂(g) + O₂ (g) → 2NO₂(g)     slow

Deduce the rate expression for the mechanism.

Explain why transition metals exhibit variable oxidation states in contrast to alkali metals.

Suggest, giving a reason, the percentage of each isomer from the S_N1 reaction.

Predict the chemical shifts and integration for each signal in the ¹H NMR spectrum for ethanol using section 27 of the data booklet.

Which molecules contain two pi ($\mathrm{\pi }$) bonds?

I.   HCN
II.  H₂CO₃
III. H₂C₂O₄

A.  I and II only

B.  I and III only

C.  II and III only

D.  I, II and III

Which complex ion contains a central ion with an oxidation state of +3?

A.  [PtCl₆]²⁻

B.  [Cu(H₂O)₄(OH)₂]

C.  [Ni(NH₃)₄(H₂O)₂]²⁺

D.  [Co(NH₃)₄Cl₂]⁺

Calculate the entropy change, ΔS, in J K⁻¹mol⁻¹, for this reaction.

Chemistry 2e, Chpt. 21 Nuclear Chemistry, Appendix G: Standard Thermodynamic Properties for Selected Substances https://openstax.org/books/chemistry-2e/pages/g-standard-thermodynamic-properties-for- selectedsubstances# page_667adccf-f900-4d86-a13d-409c014086ea © 1999-2021, Rice University. Except where otherwise noted, textbooks on this site are licensed under a Creative Commons Attribution 4.0 International License. (CC BY 4.0) https://creativecommons.org/licenses/by/4.0/.

The concentration of excess sodium hydroxide was 0.362 mol dm⁻³. Calculate the pH of the solution at the end of the experiment.

Calculate the initial pH before any sodium hydroxide was added, using section 21 of the data booklet.

A student electrolyzed aqueous iron(II) sulfate, FeSO₄ (aq), using platinum electrodes. State half-equations for the reactions at the electrodes, using section 24 of the data booklet.

Calculate the standard Gibbs free energy change, ΔG^Θ, in J, of the redox reaction in (ii), using sections 1 and 24 of the data booklet.

E^Θ (BrO₃⁻ / Br⁻) = +1.44 V

Which equation represents hydration enthalpy?

A.  Na⁺(g) → Na⁺(aq)

B.  Na⁺(aq) → Na⁺(g)

C.  NaCl (s) → NaCl (aq)

D.  NaCl (aq) → NaCl (s)

Calculate the equilibrium constant, K_c, for this reaction at 298 K. Use your answer to (d)(iii) and sections 1 and 2 of the data booklet.

(If you did not obtain an answer to (d)(iii) use a value of 2.0 kJ mol⁻¹, although this is not the correct answer).

Justify why K₂O has a lower lattice enthalpy (absolute value) than Na₂O.

Explain the mechanism for the nitration of benzene, using curly arrows to indicate the movement of electron pairs.

A scientist wants to investigate the catalytic properties of a thin layer of rhenium metal on a graphite surface.

Describe an electrochemical process to produce a layer of rhenium on graphite.

Predict two other chemical properties you would expect rhenium to have, given its position in the periodic table.

Phenylethene is manufactured from benzene and ethene in a two-stage process. The overall reaction can be represented as follows with ΔG^θ = +10.0 kJ mol⁻¹ at 298 K.

Calculate the equilibrium constant for the overall conversion at 298 K, using section 1 of the data booklet.

Which is correct for the reaction H₂O (g) → H₂O (l) ?

A. Enthalpy increases and entropy increases.

B. Enthalpy decreases and entropy increases.

C. Enthalpy increases and entropy decreases.

D. Enthalpy decreases and entropy decreases.

Which of the following transitions in the hydrogen atom emits the least energy?

A. n = 2 to n = 1

B. n = 3 to n = 1

C. n = 4 to n = 2

D. n = 4 to n = 3

Bubbles of gas were also observed at another electrode. Identify the electrode and the gas.

Electrode number (on diagram):

Name of gas: 

Describe, using a suitable equation, how the buffer solution formed during the titration resists pH changes when a small amount of acid is added.

What is the correct explanation for the colour of [Cu(H₂O)₆]²⁺?

A. Light is absorbed when an electron moves to a d orbital of higher energy.

B. Light is released when an electron moves to a d orbital of higher energy.

C. Light is absorbed when electrons move from the ligands to the central metal ion.

D. Light is absorbed when electrons move between d and s orbitals.

(i) Using the graph, explain the order of reaction with respect to sodium thiosulfate.

(ii) In a different experiment, this reaction was found to be first order with respect to hydrochloric acid. Deduce the overall rate expression for the reaction.

An iron rod is electroplated with silver. Which is a correct condition for this process?

A. The silver electrode is the positive electrode.

B. The iron rod is the positive electrode.

C. The electrolyte is iron(II) sulfate.

D. Oxidation occurs at the negative electrode.

Which combination correctly describes the geometry of ${{\mathrm{BrF}}_4}^{-}$?

Outline why transition metals form coloured compounds.

Suggest a suitable indicator for the titration of hydrazine solution with dilute sulfuric acid using section 22 of the data booklet.

State the reagents used in the two-stage conversion of nitrobenzene to aniline.

Which is true of an Arrhenius plot of $\ln k$ (y-axis) against $\frac{1}{T}$?

A.     The graph goes through the origin.

B.     The activation energy can be determined from the gradient.

C.     The intercept on the x-axis is the activation energy.

D.     The intercept on the y-axis is the frequency factor, A.

Corrosion of iron is similar to the processes that occur in a voltaic cell. The initial steps involve the following half-equations:

Fe²⁺(aq) + 2e^– $\rightleftharpoons$ Fe(s)

$\frac{1}{2}$O₂(g) + H₂O(l) + 2e^– $\rightleftharpoons$ 2OH^–(aq)

Calculate E ^θ, in V, for the spontaneous reaction using section 24 of the data booklet.

Explain why iron forms many different coloured complex ions.

Zinc is used to galvanize iron pipes, forming a protective coating. Outline how this process prevents corrosion of the iron pipes.

State one method that can be used to measure the rate for this reaction.

The Arrhenius equation, $k=A{e}^{-\frac{Ea}{RT}}$, gives the relationship between the rate constant and temperature.

State how temperature affects activation energy.

The pK_a of an anthocyanin is 4.35. Determine the pH of a 1.60 × 10^–3 mol dm^–3 solution to two decimal places.

Explain why an aluminium-titanium alloy is harder than pure aluminium.

Explain why the major organic product is 2-bromopropane and not 1-bromopropane.

At 700 ºC, the equilibrium constant, K_c, for the reaction is 1.075 × 10⁸.

2H₂ (g) + S₂ (g) $\rightleftharpoons$ 2H₂S (g)

Which relationship is always correct for the equilibrium at this temperature?

A. [H₂S]² < [H₂]² [S₂]

B. [S₂] = 2[H₂S]

C. [H₂S] < [S₂]

D. [H₂S]² > [H₂]²[S₂]

[CoCl₆]^3– is orange while [Co(NH₃)₆]³⁺ is yellow. Which statement is correct?

A. [CoCl₆]^3– absorbs orange light.

B. The oxidation state of cobalt is different in each complex.

C. The different colours are due to the different charges on the complex.

D. The different ligands cause different splitting in the 3d orbitals.

Which indicator is appropriate for the acid-base titration shown below?

A. Thymol blue (pK_a = 1.5)
B. Methyl orange (pK_a = 3.7)
C. Bromophenol blue (pK_a = 4.2)
D. Phenolphthalein (pK_a = 9.6)

The standard free energy change, ΔG^θ, for the above reaction is –103 kJ mol^–1 at 298 K.

Suggest why ΔG^θ has a large negative value considering the sign of ΔH^θ in part (a).

Predict, giving a reason, the direction of movement of electrons when the standard nickel and manganese half-cells are connected.

Which is most likely to hydrolyse via a S_N1 mechanism?

A.  CH₃CHBrCH₂CH₃

B.  (CH₃)₂CHBr

C.  (CH₃)₃CBr

D.  CH₃CH₂CH₂CH₂Br

Which represents electron affinity?

A.  Al²⁺(g) → Al³⁺(g) + e⁻

B.  C (g) + e⁻ → C⁻(g)

C.  Cl₂(g) → 2Cl (g)

D.  S (s) → S⁺(g) + e⁻

Which compound rotates the plane of plane-polarized light?

A.  CH₃C(CH₃)ClCH₃

B.  CH₃CH₂CHClCH₃

C.  CH₃C(Cl)₂CH₃

D.  CH₃CClBrCH₃

What happens to the mass of each copper electrode when aqueous copper(II) sulfate solution is electrolysed?

The equilibrium constant, K_c, has a value of 1.01 at 298 K.

Calculate ΔG^⦵, in kJ mol^–1, for this reaction. Use sections 1 and 2 of the data booklet.

Deduce the change in enthalpy, ΔH, in kJ, when 56.00 g of ethanol is burned. Use section 13 in the data booklet.

What is the enthalpy of solution of MgF₂(s) in kJ mol⁻¹?

Lattice enthalpy of MgF₂(s) = 2926 kJ mol⁻¹

Hydration enthalpy of Mg²⁺(g) = −1963 kJ mol⁻¹

Hydration enthalpy of F⁻(g) = −504 kJ mol⁻¹

A.     2926 − 1963 + 2(−504)

B.     2926 − 1963 − 504

C.     −2926 − (−1963) − (−504)

D.     −2926 − (−1963) − 2(−504)

The C–N bonds in urea are shorter than might be expected for a single C–N bond. Suggest, in terms of electrons, how this could occur.

Determine, showing your working, the spontaneity of the reaction in (ii) at 25 °C.

Deduce the rate expression for the reaction.

Write an equation to show ammonia, NH₃, acting as a Brønsted–Lowry base and a different equation to show it acting as a Lewis base.

The change in the free energy for the reaction under standard conditions, ΔG^Θ, is −514 kJ at 298 K.

Determine the value of E^Θ, in V, for the reaction using sections 1 and 2 of the data booklet.

State the type of bond fission that takes place in a S_N1 reaction.

The graph shows Gibbs free energy of a mixture of N₂O₄(g) and NO₂(g) in different proportions.

N₂O₄(g) $\rightleftharpoons$ 2NO₂(g)

Which point shows the system at equilibrium?

Determine the equilibrium constant, K, for this reaction at 25 °C, referring to section 1 of the data booklet.

If you did not obtain an answer in (c)(iii), use ΔG = –43.5 kJ mol⁻¹, but this is not the correct answer.

Deduce the rate expression for this reaction.

What are the signs of ΔH^Θ and ΔS^Θ for the reaction, which is spontaneous at low temperature and non-spontaneous at very high temperature?

ΔG^Θ = ΔH^Θ − TΔS^Θ

SO₃ (g) + CaO (s) → CaSO₄ (s)

Deduce the rate expression.

In the electrolysis apparatus shown, 0.59 g of Ni is deposited on the cathode of the first cell.

What is the mass of Ag deposited on the cathode of the second cell?

A.  0.54 g

B.  0.59 g

C.  1.08 g

D.  2.16 g

What are the products when dilute aqueous copper (II) nitrate is electrolysed using platinum electrodes?

E^⦵ (Cu | Cu²⁺) = –0.34 V.

This cell causes the electrolytic reduction of water on the steel. State the half-equation for this reduction.

State the number of $\text{σ}$ (sigma) and $\mathrm{\pi }$ (pi) bonds in Compound A.

Identify the isomer of Compound B that exists as optical isomers (enantiomers).

Explain why the reaction produces more (CH₃)₃COH than (CH₃)₂CHCH₂OH.

Write an equation for the reaction between the acids to produce the electrophile, NO₂⁺.

Calculate the entropy change of reaction, ΔS^⦵, in J K⁻¹ mol⁻¹.

Identify the wavenumber of one peak in the IR spectrum of benzoic acid, using section 26 of the data booklet.

Plot the relative values of the first four ionization energies of sodium.

Calculate values for the following changes using section 8 of the data booklet.

ΔH_atomisation (Na) = 107 kJ mol⁻¹
ΔH_atomisation (O) = 249 kJ mol⁻¹

$\frac{1}{2}$O₂(g) → O^2- (g):

Na (s) → Na⁺ (g):

Identify the spectroscopic technique that is used to measure the bond lengths in solid benzoic acid.

Calculate a value for the equilibrium constant, K_c, at 298 K, giving your answer to two significant figures. Use your answer to (f)(ii) and section 1 of the data booklet. 

(If you did not obtain an answer to (f)(ii), use −140 kJ mol⁻¹, but this is not the correct value.)

Calculate the standard electrode potential, in V, when the Fe²⁺ (aq) | Fe (s) and Cu²⁺ (aq) | Cu (s) standard half-cells are connected at 298 K. Use section 24 of the data booklet.

The minor product, C₆H₅–CH₂–CH₂Br, can exist in different conformational forms (isomers).

Outline what this means.

Explain why the first ionization energy of nitrogen is greater than both carbon and oxygen.

Nitrogen and carbon:

Nitrogen and oxygen:

The benzene ring of phenylethene reacts with the nitronium ion, NO₂⁺, and the C=C double bond reacts with hydrogen bromide, HBr.

Compare and contrast these two reactions in terms of their reaction mechanisms.

Similarity: 

Difference:

Which statement is correct about a catalyst?

A. It decreases the activation energy of the forward reaction but not the reverse.

B. It increases the proportion of products to reactants in an equilibrium.

C. It decreases the enthalpy change of the reaction.

D. It changes the mechanism of the reaction.

Which can be identified using infrared (IR) spectroscopy?

A. functional groups

B. molar mass

C. 3-D configuration

D. bond angle

Deduce why the Cu(I) solution is colourless.

Three cells with platinum electrodes are connected in series to a DC power supply.

What is the ratio of moles formed at each cathode (negative electrode)?

X-ray crystallography of a metal crystal produces a diffraction pattern of bright spots.

Using X-rays of wavelength 1.54 × 10⁻¹⁰ m, the first bright spots were produced at an angle θ of 22.3° from the centre.

Calculate the separation between planes of atoms in the lattice, in meters, using section 1 of the data booklet.