Question 1

Marks: 1

A student mixed 30.0 cm³of 0.0250 mol dm^-3potassium hydroxide solution with 30.0 cm³of 0.0250 mol dm^-3 nitric acid. The temperature rose by 0.50 ^oC. Assume no heat was lost to the surroundings.

The mixture had a specific heat capacity of 4.18 J g ^-1 K^-1.

What is the molar enthalpy change for the reaction?

$- \frac{30 \times 4.18 \times 0.5 \times 1000}{0.025 \times 30}$
$- \frac{60 \times 4.18 \times 0.5}{0.025 \times 30}$
$- \frac{0.025 \times 30}{60 \times 4.18 \times 0.5 \times 1000}$
$- \frac{60 \times 4.18 \times 0.5}{0.025 \times 30}$

Question 2

Marks: 1

An experiment was carried out to determine the approximate value for the molar enthalpy change of neutralisation.

75 cm³ of 3.00 mol dm^–3 hydrochloric acid was placed in a polystyrene beaker of negligible heat capacity. Its temperature was recorded, and then 75 cm³ of
3.00 mol dm⁻³potassium hydroxide at the same temperature was quickly added, and the solution stirred.

The temperature rose by 14 °C. The resulting solution may be considered to have a specific heat capacity of 4.18 J g^-1K^-1.

Which calculation below is correct?

$- \frac{(75 \times 4.18 \times 14)}{(6.0 \times 0.150)}$ J mol^-1
$- \frac{(150 \times 4.18 \times 14)}{(3.0 \times 0.075)}$ J mol^-1
$- \frac{(150 \times 4.18 \times 14)}{(3.0 \times 75.0)}$ J mol^-1
$- \frac{(75 \times 4.18 \times 287)}{(6.0 \times 0.150)}$ J mol^-1

Question 3

Marks: 1

The table below discusses three types of enthalpy change:

‘+’ means that this type of standard enthalpy change can only have positive values,

‘–’ means that this type of standard enthalpy change can only have negative values,

‘+ / –’ means that either positive or negative values are possible.

Which row is correct?

	formation	combustion	neutralisation
A	+	+	+ / –
B	+ / –	+	+ / –
C	+ / –	–	–
D	–	–	+

Question 4

Marks: 1

Using a spirit burner, ethanol is used to heat a container of water.

In this experiment:

Mass of ethanol burned, g	a
Mass of water, g	b
Specific heat capacity of water, J g^–1 K^–1	d
Temperature rise, °C	y

How much heat energy is absorbed by the water?

ady
bdy
bd(y+273)
(y+273) / ad

Question 5

Marks: 1

An iron block with a mass of 0.11 kg absorbs 504 J of heat energy. What is the temperature rise in K?

Specific heat capacity of iron = 0.448 J g^–1 K^–1

1.02 x10⁴
1.10
10.23
9.78 x 10^-2

Question 6

Marks: 1

Which statements are correct for an endothermic reaction?

The products are more stable than the reactants
The enthalpy change is positive
The temperature of the surroundings decreases

I and II only
I and III only
II and III only
I, II and III

Question 7

Marks: 1

Which assumptions are correct when calculating the enthalpy change for a reaction in solution?

The density of the solution is 1 g cm^-3
The specific heat capacity of the solution is 4.18 J g^-1 K^-1
The correct stoichiometric quantities of reactants for a complete reaction are used

I and II only
I and III only
II and III only
I, II and III

Question 8

Marks: 1

What is the closest integer value of the temperature change for this reaction, from the graph

8
9
11
35

Question 9

Marks: 1

Which enthalpy changes correctly describe the following reactions?

Reaction 1: HNO₃ (aq) + NH₃ (aq) → NH₄NO₃ (aq)

Reaction 2: CuCO₃ (s) → CuO (s) + CO₂ (g)

Reaction 3: S (s) + O₂ (g) → SO₂ (g)

	ΔH^Ө_c	ΔH^Ө_f	ΔH^Ө_neut	ΔH^Ө_r
A	2	2	1	3
B	3	2	1	2
C	3	3	1	2
D	2	3	1	3

Question 10

Marks: 1

Which systems are correctly described?

Matter and energy can be transferred across the boundary of an open system
Only matter can be transferred across the boundary of a closed system
Matter and energy cannot be transferred across the boundary of an isolated system

I and II only
I and III only
II and III only
I, II and III

DP IB Chemistry: HL

Topic Questions

5.1 Energetics

Question 1

Question 2

Question 3

Question 4

Question 5

Question 6

Question 7

Question 8

Question 9

Question 10

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