Answer to Question #118045 in General Chemistry for george

Question

What would happen to the concentrations of each substance in the system
H2(g) + I2(g)  Δ2 HI(g) upon adding (a) more H2 and (b) more HI.
2. 2 CO2(g) + N2(g) == C2N2(g) + 2 O2(g) ΔH = + 1095.9 kJ

(a) if the volume of the reaction vessel is increased
(b) if O2 is added
(c) if the temperature is increased
(d) if the concentration of N2 is increased

Answer 1

Both the questions are based on Le-chatlier's principle let's discuss it

Le Chatelier's principle states that if a dynamic equilibrium is disturbed by changing the conditions, the position of equilibrium shifts to counteract the change to reestablish an equilibrium. If a chemical reaction is at equilibrium and experiences a change in pressure, temperature, or concentration of products or reactants, the equilibrium shifts in the opposite direction to offset the change.

1)$H_2(g) + I_2(g) \iff 2 HI$ .

If hydrogen is added then the equilibrium will oppose the change and hence will try to reduce it concentration by producing more HI thus the reaction will shift forward

If HI is added then equilibrium will shift in backward direction reducing the concentration of the HI

2) $2 CO_2(g) + N_2(g) \iff C_2N_2(g) + 2 O_2(g)$

(a) there will be no effect of volume as we can the stochiometric coefficient is same on reactant and as well as product side $\Delta n=0$

(b) if oxygen is increased then equilibrium will try to reduce it hence will shift toward backward side

(c) if the temperature is increased then the equilibrium will try to reduce it by shifting towards forward side as $\Delta H$ is positive here

(d)if nitrogen is increased then the equilibrium will try to reduce it by shifting in forward direction