Physical Chemistry 1: Energetics Multiple Choice Questions

1. What is the amount of energy, in Joules, needed to raise the temperature of 1 mole of water by 15℃? The specific heat capacity of water is 4.18 J g-1 K-1.

Correct! Wrong!

2. Which of the following equations does NOT represent the enthalpy of combustion of an element?

Correct! Wrong!

3. Which of the following statements are correct?


i) The enthalpy of formation of an element is zero by definition
ii) The enthalpy of combustion of an element is zero by definition
iii) The enthalpy change of reaction is the heat change at constant pressure
iv) According to Hess’s Law the enthalpy change for a chemical reaction is the same, whatever route is taken from reactants to products

Correct! Wrong!

4. The enthalpy change for the thermal decomposition of CaCO3 is +177 kJ mol-1.

What is the enthalpy change in kJ for the thermal decomposition of 15.5.g of CaCO3?

Correct! Wrong!

5. The enthalpy of combustion of ethanol was determined by calorimetry and was found to be -1256 kJ mol-1

The data book value for the standard enthalpy of combustion of ethanol is -1371 kJ mol-1.

What is the percentage error of the value determined by calorimetry?

Correct! Wrong!

6. Which of the following reactions has a negative enthalpy change?

Correct! Wrong!

7. Use the data in the table below to help you answer the following question:

Compound ΔcHΘ/kJ mol-1
Benzene -3267
Carbon -393.5
Hydrogen -286


What is the enthalpy of formation of Benzene in in kJ mol-1?

6C(s) + 3H2(g) → C6H6(l)

Correct! Wrong!

8. Use the data in the table below to help you answer the question.

Compound ΔcHΘ/kJ mol-1
Ethanol -1367
Methane -890
Ethane -1560
Methanol -726


The complete combustion of 0.500 moles of which of the following compounds would result in the greatest increase in the temperature of the surroundings?

Correct! Wrong!

9. Use the data in the table below to help you answer the following question:

Compound ΔfHΘ/kJ mol-1
Propane 104.7
Carbon Dioxide -393.5
Water -286


What is standard enthalpy of combustion of propane in kJ mol-1?

C3H8(g) + 5O2(g) → 3CO2(g) + 4H2O(l)

Correct! Wrong!

10. The mean bond enthalpies of several bonds are shown in the table below.

Bond Bond Enthalpy/ kJ mol-1
P-H 322
Cl-Cl 244
H-Cl 428
P-Cl 326


Use this data to answer the following question.

What is the enthalpy change, in kJ mol-1, for the reaction between Phosphine and Chlorine?

PH3(g) + 4Cl2(g) → PCl5(g) + 3HCl(g)

Correct! Wrong!