Question

solve this

chemistry class XI​

Answer 1

Basic question of thermodynamics

Solution:-

i) C(graphite) +O2=>CO2:∆H°=xKj/mol

ii) C(graphite)+O2/2 =>CO2:∆H°=ykj/mol

iii)CO(g) +O2/2=>CO2 :∆H°=zKJ/mol

On adding equation ii) and iii) i.e z+y ,we get

C(graphite)+CO+(1/2+1/2)O2=>CO+CO2

Cancelling CO from both side ,we get

C(graphite)+O2=>CO2

this is equal to equation reaction of equation i) i.e x

so x=z+y ,is the right answer

From the above theoretical ,we can say that if we will practically intermix the reaction of equation ii) and equation iii) ,then the resultant product that we will get will be the reaction of the equation first.

Answer 2

The algebraic  relationships given is (c) x = y + z

From question, the change in enthalpy due to formation of CO₂

Δf° H (CO₂) = x

From question, the change in enthalpy due to formation of CO

Δf° H (CO) = y

The change in enthalpy due to formation of reactant:

ΔrH = Δf° H (CO₂) - Δf° H (CO) - 1/2 Δf° H (O₂)

∵ 1/2 Δf° H (O₂) = 0

Now,

ΔrH = Δf° H (CO₂) - Δf° H (CO) - 0

∴ z = x - y

∴ x = y + z