Answer

Chemical Equilibria|Le Chatelier's Principle|Factors Affecting Chemical equilibria| The Haber Process|The Contact Process|Equilibrium Constants

=Question 1= Consider the following reaction:

N2 (g) + 3H2(g) <=> 2NH3 (g) ∆H = -ve

State 2 conditions which might be chnaged to increase the yield of ammonia gas.

Answer:

Condition 1: An increase in pressure; side with less number of moles will be favoured, that is right hand side and thus more ammonia will be produced.

Condition 2: A decrease in temperature; enthalpy chnage for the reaction is exothermic. This means that a decrease in temperature will favour side which will liberate energy, that is forward reaction. Thus more ammonia is prodcued.

=Question 2=

(a) What is meant by a reversible reaction? (b) An increase in temperature of the following reversible reaction causes more of the CuSO4 (aq) to be formed. What can be deduced about the enthalpy of the reaction? Explain your deductions.

CuSO4 (aq) <=> CuSO4. 5H2O

Answer:

(a) A reversible reaction is one which can go both forward and backward.

(b) Enthalpy change for the reaction is exothermic. An increase in temperature will thus favour the backward reaction so as to decrease the temperature.

=Question 3=

Colourless N2O4 is in equilibrium with brown NO2 according to the following equation.

N2O4 <=> 2NO2

If the mixture is in a syringe and compressed, state what will be observed and explain the observations using Le Chatelier's Principle.

Answer:

Compressing the syring implies that pressure is increased. Thus equilibrium will shift to side with less number of moles that is to left hand side. Mixture will turn paler and paler due to formation of colourless N2O4.