Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Unit
Physical Chemistry
442 practice questions
Topics covered
Practice questions
61–70 of 442
Question 61
2 marks · Easy
Answer and see the solution →A student’s value for the enthalpy change of combustion of methanol is much less exothermic than the accepted value found in data books. Explain two possible sources of error or limitations in the student’s calorimetry experiment.
Question 62
1 mark · Easy
Answer and see the solution →Name the piece of apparatus commonly used as a container for solution reactions in simple calorimetry experiments.
Question 63
3 marks · Easy
Answer and see the solution →(a)[1 mark]A student adds 40 g of water to a beaker. The initial temperature of the water is 22.0°C. A chemical reaction causes the temperature to rise to 30.5°C.
Calculate the temperature change, ΔT, for the water.
(b)[2 marks]The specific heat capacity of water is 4.18 J/g°C. Using your answer to part (a), calculate the heat energy gained by the water, Q, in joules. Give your answer to 2 significant figures.
Question 64
2 marks · Easy
Answer and see the solution →A student dissolves 3.21 g of potassium nitrate in 50 g of water. The temperature of the water falls by 5.0°C. The specific heat capacity of water is 4.18 J/g°C. Calculate the molar enthalpy change (ΔH) of solution for potassium nitrate. (Relative formula mass of KNO₃ = 101)
Give your answer in kJ/mol to 2 significant figures. Show your working.
Question 65
2 marks · Normal
Answer and see the solution →Describe how you would measure the enthalpy change of solution for a solid salt dissolving in water using a simple calorimetry experiment. Include two key steps in your answer.
Question 66
4 marks · Normal
Answer and see the solution →A student carries out a calorimetry experiment to find the amount of heat released in a neutralisation reaction between hydrochloric acid and sodium hydroxide. She mixes 50 g of solution at 21.0°C with sodium hydroxide. After the reaction, the temperature rises to 27.5°C. The specific heat capacity of water is 4.18 J/g°C.
(a)[1 mark]Calculate the temperature change (ΔT) of the solution.
(b)[1 mark]Write the equation used to calculate the heat energy change (Q) in this experiment.
(c)[2 marks]Calculate the total heat energy, in joules, released in this reaction. Show your working.
Question 67
3 marks · Normal
Answer and see the solution →In a calorimetry experiment, 1.25 g of magnesium reacts completely with excess hydrochloric acid. The temperature of the 100 g acid solution rises by 9.8°C. The specific heat capacity of the solution is 4.18 J/g°C. Calculate the molar enthalpy change (ΔH) of this reaction in kJ/mol. The relative atomic mass of magnesium, Mg, is 24.
Question 68
3 marks · Normal
Answer and see the solution →A student finds that their calculated enthalpy change of combustion for ethanol is much less exothermic than the value from data books. Explain three possible sources of error in their calorimetry experiment that could have led to this result.
Question 69
4 marks · Normal
Answer and see the solution →The table shows some data from a calorimetry experiment measuring the enthalpy change of a displacement reaction between iron and copper(II) sulfate:
Data from calorimetry experiment Volume of copper(II) sulfate solution / cm³ Mass of iron used / g Initial temperature / °C Maximum temperature / °C Specific heat capacity / J/g°C 60 2.4 18.4 24.7 4.18 (a)[1 mark]Calculate the temperature change (ΔT) for this reaction.
(b)[2 marks]Assume the density of the solution is 1 g/cm³. Calculate the heat energy change, Q, in joules.
(c)[1 mark]Suggest one assumption made in this calculation.
Question 70
1 mark · Normal
Answer and check →Which value must be measured directly in a calorimetry experiment in order to calculate the heat energy released using the equation Q = mcΔT?
- A.The temperature change of the water
- B.The pressure inside the calorimeter
- C.The colour of the solution
- D.The rate of reaction