Energy changes - Jamb Chemistry Past Questions and Answers

Question 41:

• JAMB 1999

In order to remove one electron from a 3S orbital of gaseous sodium atom, about 496KJMol^-1 of energy is required. This energy is referred to as

A. Electron affinity
B. Ionization energy
C. Activation evergy
D. Electronegativity

Question 42:

• JAMB 1999

The entropy and enthalpy of a system are a measure of

A. Degree of disorderlinesss and heat content respectively
B. Heat content and degree of disorderliness respectively
C. Heat content of a system only
D. Degree of disorderliness only

Question 43:

• JAMB 1999

RS_(aq) + HF_(aq) → RF_(s) + HS_(aq)
ΔH = -65.7 kj mol^(-1).
From the equation above, it can be deduced that

A. The heat content of the reactants is lower than that of the products
B. The heat content of the reactants is higher than that of the products
C. The reaction is slow
D. A large amount of heat is absorbed

Question 44:

• JAMB 2000

N_2(g) + O_2(g) ↔ 2NO_(g); ΔH = + 180.6 kJ mol^-1
In the reaction above, increase in temperature will

A. Increase the quantity of N₂
B. Increase in the yield of NO
C. Decrease the yield of NO
D. Decrease the quantity of O₂

Question 45:

• JAMB 2001

C_(s) + 2S_(g) → CS_2(g)
ΔH = +89 kJ mol^-1
The chemical equation above implies that

A. Each of carbon and sulphur has 89 kJ of energy
B. Both carbon and sulphur contribute 89 kJ of energy
C. 89 kJ of energy is released
D. 89 kJ of energy is absorbed