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DP IB Chemistry: HL

Topic Questions

Home / IB / Chemistry: HL / DP / Topic Questions / 5. Energetics / Thermochemistry / 5.1 Energetics / Multiple Choice: Paper 1


5.1 Energetics

Question 1

Marks: 1

Which equation below can represent both an enthalpy change of formation and combustion?

  • CH4(g) + 2O2(g)  →  CO2(g) + 2H2O(l)

  • 2Na(s) + ½O2(g)  →  Na2O(s) 

  • HCl(aq) + NaOH(aq)  →  NaCl(aq) + H2O(l)

  • CO(g) + C(s)  →  CO2(g)

Choose your answer
  

Question 2

Marks: 1

A student carried out an experiment to determine the enthalpy change for the combustion of ethanol.

The following results were obtained by the student. The specific heat capacity of water is 4.18 J g−1 K−1.q1_5-1_ib_sl_easy_mcq

start temperature of the water

21 °C

final temperature of the water

41 °C

mass of alcohol burner before burning

259.75 g

mass of alcohol burner after burning

259.18 g

mass of glass beaker plus water

150.00 g

mass of glass beaker

50.0 g

How much of the heat energy produced by the burning of ethanol went into the water?

  • 100 x 4.18 x 20 J 

  • 150 x 4.18 x 20 J

  • 0.57 x 4.18 x 20 J

  • 100 x 4.18 x 41 J

Choose your answer
  

Question 3

Marks: 1

When a sample of ammonium chloride is added to a small beaker of water and stirred, the temperature drops as the ammonium chloride slowly dissolves in the water. 

Which statement about the process is true?

  • The process is endothermic and ΔH is -

  • The process is exothermic and ΔH is -

  • The process is endothermic and ΔH is +

  • The process is exothermic and ΔH is +

Choose your answer
  

Question 4

Marks: 1

Which statement is true about all exothermic reactions?

  • Gases are formed during the reaction

  • They give out heat 

  • The reaction is fast

  • They are combustion reactions

Choose your answer
  

Question 5

Marks: 1

Which processes have a negative enthalpy change? 

  1.  The combustion of an alcohol
  2.  The reaction between hydrochloric acid and sodium hydroxide
  3.  Water vapour condensing
  • I and II only  

  • I and III only  

  • II and III only 

  • I, II and III

Choose your answer
  

Question 6

Marks: 1

The enthalpy change of a chemical reaction can be found using the following relationship: 

q = mcΔT 

In this expression, which of the following is true?

  • m represents the amount of substance in moles

  • The temperature is measured in Centigrade

  • c is the specific heat capacity of the substance

  • The unit of q is kJ

Choose your answer
  

Question 7

Marks: 1

Which is the correct definition for the standard enthalpy of combustion?

  • The enthalpy change when the reactants in a stoichiometric equation react to give the products, under standard conditions

  • The enthalpy change when one mole of a substance is burnt in excess oxygen, under standard conditions

  • The enthalpy change when one mole of water is formed by reacting an acid and an alkali, under standard conditions

  • The enthalpy change when one mole of a product is formed from its elements, under standard conditions

Choose your answer
  

Question 8

Marks: 1

1.20 g of ethanol is combusted releasing 35 500 J of energy. 

What is the molar enthalpy change for the combustion of ethanol?

  • begin mathsize 14px style negative fraction numerator left parenthesis 35500 space cross times space 46.0 right parenthesis over denominator left parenthesis 1.20 space cross times space 1000 right parenthesis end fraction end style

  • begin mathsize 14px style negative fraction numerator left parenthesis 35500 space cross times space 1000 right parenthesis over denominator left parenthesis 1.20 space cross times space 46.0 right parenthesis end fraction end style

  • begin mathsize 14px style fraction numerator left parenthesis 35500 space cross times space 46.0 right parenthesis over denominator left parenthesis 1.20 space cross times space 1000 right parenthesis end fraction end style

  • begin mathsize 14px style fraction numerator left parenthesis 35500 space cross times space 1000 right parenthesis over denominator left parenthesis 1.20 space cross times space 46.0 right parenthesis end fraction end style

Choose your answer
  

Question 9

Marks: 1

Which enthalpy change is described as the enthalpy change when the reactants in a stoichiometric equation react, under standard conditions, to form the products?

  • ΔHӨc

  • ΔHӨneut

  • ΔHӨr

  • ΔHӨf

Choose your answer
  

Question 10

Marks: 1

Which statement describes a closed system?

  • Only matter can be transferred across the boundary

  • Only energy can be transferred across the boundary

  • Energy and matter can be transferred across the boundary

  • Energy and matter cannot be transferred across the boundary

Choose your answer