Question

1) For this reaction,

SiCl4 (l)+ 2H2O(g) <-> SiO2 (s) + 4HCl (g) DeltaH = -127 KJ

Predict the effect increase (i), decrease(d) or no change(nc) that each change has on the QUANTITY for the equilibrium mixture. Assume that each change is applied separately to the system.

Change Quantity Effect
increase in pressure amount of H2O
i, d or nc

decrease temp amount of SiCl4 i d or nc
increase temp Kc i d or nc
increase temp amount of H2O i d or nc
add H2O amount of SiCl4 i d or nc
add SiO2 amount of HCl i d or nc
add HCl amount of SiO2 i d or nc

Answer 1

Answer:

a) Increase

b) the amount of SiCl₄ will decrease.

c) K will increases.

d)  H₂O will increase.

e)  SiCl₄ will decrease

f) HCl will decrease.

g) SiO₂ will decrease

Explanation:

The equilibrium changes are explained by Le-Chatelier's Principle.

If we apply a change to an equilibrium system then it shifts to the side where the effect of stress can be released.

a) Change : Increase in pressure

Quantity : amount of water

Change: We are increasing the pressure it will decrease the volume and hence will increase the moles per unit volume. so the system will move in the direction where the number of gaseous moles are less. It will move towards reactant side. thus the amount of water will increase.

b) Change : decrease in temperature

Quantity : amount of SiCl₄

As this is an exothermic reaction, the decrease in temperature will shift the reaction towards product side and hence the amount of SiCl₄ will decrease.

c)

Change : Increase in Temperature

Quantity: Kc

The equilibrium constant will increase as it increases with temperature.

d) Change : increase in temperature

Quantity : amount of H₂O

As this is an exothermic reaction, the increase in temperature will shift the reaction towards reactant side and hence the amount of H₂O will increase.

e) Change : Add H₂O

Quantity: Amount of SiCl₄

As we are adding reactant to the equilibrium, the equilibrium will shift towards product side thus the amount of SiCl₄ will decrease

f) Change : Add SiO₂

Quantity: Amount of HCl

As we are adding product, the equilibrium will shift in reactant side and thus there will be decrease in amount of HCl.

g) Change : Add HCl

Quantity: Amount of SiO₂

As we are adding product to the equilibrium the equilibrium will shift in reactant side and thus there will be decrease in amount of SiO₂