Energy changes - Jamb Chemistry Past Questions and Answers

Question 51:

• JAMB 2004

2CO_(g) + O_2(g) → 2CO_2(g)
Given that ΔH[CO]is -110.4 kJmol^-1 and ΔH[CO₂] is -393.0 kJmol^-1, the energy change for the reaction above is

A. -503.7 kJ
B. -282.6 kJ
C. +282.6 kJ
D. +503.7 kJ

Question 52:

• JAMB 2004

Which of the following hydrogen halides the highest entropy value?

A. HF
B. HCl
C. HBr
D. HI

Question 53:

• JAMB 2004

N₂O_4(g) ↔ 2NO_2(g)
In the endothermic reaction above, more product formation will be favoured by

A. A constant volume
B. An increase in pressure
C. A decrease in pressure
D. A decrease in volume

Question 54:

• JAMB 2005

2H₂ + O₂2 → H₂+O ΔH = -571kJ
In the equation above, how much heat will be liberated if 12.0g of hydrogen is burnt in excess oxygen?

A. -1142 kJ
B. -571 kJ
C. +1142 kJ
D. -1713 kJ

Question 55:

• JAMB 2005

The pressure of 100cm³ of oxygen at 35^oC is 750mmHg. What will be the volume of gas if the pressure is reduced to 100mmHg without changing the temperature?

A. 650 cm³
B. 850 cm³
C. 580 cm³
D. 750 cm³