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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

In a calorimetric experiment 2.50 g of a fuel is burnt in oxygen. 30 % of the energy released during the combustion is absorbed by 500 g of water, the temperature of which rises from 25 °C to 68 °C. 

The specific heat capacity of water is 4.2 J g–1 K–1

What is the total energy released per gram of fuel burnt?

  • begin mathsize 14px style fraction numerator 500 space cross times space 4.2 space cross times space left parenthesis 68 space minus space 25 right parenthesis over denominator 2.5 end fraction end style

  • begin mathsize 14px style fraction numerator 500 space cross times space 4.2 space cross times space left parenthesis 273 space plus space left parenthesis 68 space minus space 25 right parenthesis right parenthesis space cross times 100 over denominator 30 space cross times space 2.5 end fraction end style

  • begin mathsize 14px style fraction numerator 500 space cross times space 4.2 space cross times space left parenthesis 68 space minus space 25 right parenthesis space cross times space 100 over denominator 30 space cross times space 2.5 end fraction end style

  • begin mathsize 14px style fraction numerator 500 space cross times space 4.2 space cross times space left parenthesis 68 space minus space 25 right parenthesis space cross times space 100 over denominator 30 end fraction end style

Choose your answer
  

Question 2

Marks: 1

The reaction of hydrochloric acid with sodium hydroxide produced an overall temperature increase of 24.4 K. 

Given the following data, how much thermal energy was evolved during this reaction? 

Initial temperature of 25.0 cm3 hydrochloric acid = 17.6 oC

Initial temperature of 25.0 cm3 sodium hydroxide = 18.5 o

The specific heat capacity of water is 4.18 J g-1 K-1.

  • (25.0 x 4.18 x 6.8) + (25.0 x 4.18 x 5.9)

  • begin mathsize 14px style fraction numerator left parenthesis 25.0 space cross times space 4.18 space cross times space 6.8 right parenthesis space plus space left parenthesis 25.0 space cross times space 4.18 space cross times space 5.9 right parenthesis over denominator 2 end fraction end style

  • 50.0 x 4.18 x begin mathsize 14px style open parentheses fraction numerator 6.8 space plus space 5.9 over denominator 2 end fraction close parentheses end style

  • (50.0 x 4.18 x 6.8) + (50.0 x 4.18 x 5.9)

Choose your answer
  

Question 3

Marks: 1

The temperature rise when 0.1 MJ of heat energy is absorbed by 2.5 kg of solid aluminium is 44.4 oC. 

What is the specific heat capacity of aluminium, in J g-1 K-1?

  • begin mathsize 14px style fraction numerator 100000 over denominator 2.5 space cross times space 44.4 end fraction end style

  • begin mathsize 14px style fraction numerator 100000 over denominator 2500 space cross times space 44.4 end fraction end style

  • begin mathsize 14px style fraction numerator 0.1 over denominator 2.5 space cross times space 44.4 end fraction end style

  • begin mathsize 14px style fraction numerator 0.1 over denominator 2500 space cross times space 44.4 end fraction end style

Choose your answer
  

Question 4

Marks: 1

An iron cube, with a mass of 0.5 kg, increases in temperature by 12.7 K when heated. 

The specific heat capacity of iron is 0.448 J K-1 g-1

What is the enthalpy change, in kJ mol-1, for heating the iron cube?

  • 0.448 x 12.7 x 55.85

  • begin mathsize 14px style fraction numerator 0.448 cross times 12.7 cross times 500 squared over denominator 1000 space cross times space 55.85 end fraction end style

  • begin mathsize 14px style fraction numerator 0.448 space cross times space 12.7 space cross times space 55.85 over denominator 1000 end fraction end style

  • begin mathsize 14px style negative fraction numerator 0.448 space cross times space 12.7 space cross times space 55.85 over denominator 1000 end fraction end style

Choose your answer
  

Question 5

Marks: 1

When completing experiments to measure enthalpy change for exothermic processes, which of the following is not a reason for the experimental data to be lower than the expected value?

  • Heat loss through convection

  • Water vapour released as a product

  • An inadequate supply of oxygen during combustion

  • Heat transfer to the system

Choose your answer
  

Question 6

Marks: 1

Heptathiepane, S7, can undergo complete combustion to form sulfur dioxide. 

S7 (s) + 7O2 (g) → 7SO2 (g) 

Which enthalpy changes can be used to describe this reaction?

 

 

ΔHfθ

ΔHcθ

ΔHr

A

x

B

x

C

x

x

D

x

x

    Choose your answer
      

    Question 7

    Marks: 1

    A student obtained the following experimental results for the enthalpy of combustion of cyclohexane (C6H12). 

    Mass of water / g

    50.00

    Initial temperature of the water / °C

    19.60

    Initial mass of spirit burner and cyclohexane / g

    186.79

    Final mass of spirit burner and cyclohexane / g

    186.29

     

    The student determined from this experiment that the enthalpy of combustion of cyclohexane is –1216 kJ mol–1 

    The specific heat capacity of water = 4.18 J g–1 K–1
    The relative molecular mass (Mr) of cyclohexane = 84.18 

    Which calculation will correctly determine the final temperature of the water in this experiment?

    • 19.60 + begin mathsize 14px style fraction numerator 608 over denominator 50.00 space cross times space 4.18 space cross times space 84.18 end fraction end style

    • 19.60 + begin mathsize 14px style fraction numerator 60800 over denominator 5.00 space cross times space 4.18 space cross times space 84.18 end fraction end style

    • 19.60 + begin mathsize 14px style fraction numerator 1216 space cross times space 84.18 over denominator 25.00 space cross times space 4.18 end fraction end style

    • 19.60 + begin mathsize 14px style fraction numerator 1216000 space cross times space 84.18 over denominator 25.00 space cross times space 4.18 end fraction end style

    Choose your answer
      

    Question 8

    Marks: 1

    The diagrams below show a simple calorimeter that is commonly used in the school laboratory and the more accurate chamber calorimeter.q8_5-1_ib_sl_hard_mcq

                                                   Simple calorimeter

    Chamber calorimeter

     

    Which of the following statements correctly explain why the chamber calorimeter is more accurate? 

    1. There is less heat loss
    2. There is more complete combustion
    3. There is less fuel lost
    • I and II only 

    • I and III only

    • II and III only 

    • I, II and III

    Choose your answer
      

    Question 9

    Marks: 1

    Which of the following assumptions are correct when completing the calorimetry experiment and subsequent calculations for the neutralisation of 25.0 cm3 sulfuric acid by 25.0 cm3 barium hydroxide? 

    1. That both solutions have the same initial temperature
    2. The value of m in q = mcΔT is 50 g
    3. Heat is lost to the surroundings

    • I and II only

    • I and III only

    • II and III only

    • I, II and III

    Choose your answer
      

    Question 10

    Marks: 1

    The heat produced by the combustion of magnesium is used to heat some water. 

    Which values are needed to calculate the energy transferred during the reaction? 

    1. The mass of magnesium
    2. The mass of the water
    3. The temperature change of the water
    • I and II only

    • I and III only

    • II and III only

    • I, II and III

    Choose your answer