Energy changes - Jamb Chemistry Past Questions and Answers

Question 56:

• JAMB 2005

In the diagram above which of the cures illustrates Arrhenius' law?

A. Y
B. Z
C. R
D. X

Question 57:

• JAMB 2006

H_2(g) + Br_2(g) → 2HBr_(g)
The above reaction is carried out at 25^oC. ΔH is -72 kJ mol^-1 and ΔS is - 106 J mol^-1K^-1, the reaction will

A. Not proceed spontaneously at the given
B. Proceed spontaneously at the given temperature
C. Proceed in the reverse direction at the given temperature
D. Proceed spontenously at lower temperature

Question 58:

• JAMB 2006

If the heat of combustion of hydrogen is -285.8kJ,
What is the heat of formation of water?

A. +571.6 kJ
B. -571.6 kJ
C. -285.8 kJ
D. +285.8 kJ

Question 59:

• JAMB 2007

H₃PO_4(aq) + H₂O_(l) ↔ H₂PO₄^-_(aq) + H₃O⁺_(aq)
ΔH = -13kJ at 298K
In the reaction above, an increase in temperature would

A. Slow downthe reverse reaction
B. Have no effect on the reaction
C. Favour the reverse reaction
D. Favour the forward reaction

Question 60:

• JAMB 2007

C₂H_4(g) + H_2(g) → C₂H_6(g) ΔH = -137kJ mol_-1
The reaction represented above is

A. Exothermic
B. Spontaneous
C. Endothermic
D. In equilibrium