Question 17
What is the temperature rise, in K, when 504 J of heat energy are absorbed by 0.110 kg of solid iron?
Specific heat capacity of iron = 0.448 J K−1 g−1
Question 18
The figure below shows apparatus used in an experiment to determine the enthalpy of combustion of leaf alcohol.
The alcohol is placed in a spirit burner and weighed. The burner is lit and the alcohol allowed to burn for a few minutes. The flame is extinguished and the burner is re-weighed. The temperature of the water is recorded before and after heating.
The following table shows the results obtained.
(a) Write an equation for the complete combustion of leaf alcohol
(CH3CH2CH=CHCH2CH2OH).
(1)
(b) Use the results from the table above to calculate a value for the enthalpy of combustion of leaf alcohol. Give units in your answer.
(The specific heat capacity of water is 4.18 J K−1 g−1)
(4)
(c) State how your answer to part (b) is likely to differ from the value quoted in reference sources.
Give one reason for your answer.
(2)
(d) A 50.0 g sample of water was used in this experiment.
Explain how you could measure out this mass of water without using a balance.
(2)
(Total 9 marks)