Chemistry Past Questions and Answers

2H2S(g) + SO2(g) â†’ 3S(s) + 2H2O(I). The above reaction is?

A A redox reaction H₂S is the oxidant and SO₂ is the reductant
B A redox reaction in which SO₂ is the oxidant and H₂S is the reductant
C Not a redox reaction because there is no oxidant in reaction equation
D Not a redox because there is no reductant in the reaction equation

Question 27:

Magnesium (IV) oxide is known to hasten the decomposition of hydrogen peroxide. Its main action is to?

A Increase the surface area of the reactants
B Increase the concntration of the reactants
C Lower the activation energy for the reaction
D Lower the heat of reaction, âˆ†H, for the reaction

Question 28:

1.1 g of CaCI2 dissolved in 50 cm3 of water caused a rise in temperature of3.4°C. The heat of reaction, âˆ†H for CaCI2 in kj per mole is?
(Ca = 40, CI = 35.5, specific heat of water is 4.18 jk-1

A -71.1
B -4.18
C +71.1
D +111.0

Question 29:

NO_(g) + CO_(g) â†” (1)/(2)N_2(g) + CO_2(g) âˆ†H = -89.3 kj.
What conditions would favour maximum conversion of nitrogen (II) oxide and carbon (II) oxide in the reaction above?

A Low temperature and high pressure
B High temperature and low pressure
C High temperature and high pressure
D Low temperature and low pressure

Question 30:

Which of the following equilibria is unaffected by a pressure change?

A 2NaCI(s) â†” 2Na _(I) + CI_2(g)
B H _2(g) + I_2(g) ↔ 2HI_(g)
C 2O_3(g) â†” 3O_2(g)
D 2NO_2(g) â†” N₂O_4(g)