Question

Kp/Kc for reaction for the equilibrium, A(g) ⇌ C(g)+B(g), is _______.

(Kc is the equilibrium constant in terms of concentrations, Kp is the equilibrium constant in terms of pressures, R is the gas constant, T is the temperature)

Select one:
(RT)2
(RT)-1
(RT)-2
(RT)-1.5
RT

Answer 1

Kp/Kc = RT

Further explanation

Given

Reaction

A(g) ⇌ C(g)+B(g)

Required

Kp/Kc

Solution

For reaction :

pA + qB ⇒ mC + nD

`\large {\boxed {\bold {Kc ~ = ~ \frac {[C] ^ m [D] ^ n} {[A] ^ p [B] ^ q}}}}`

While the equilibrium constant Kp is based on the partial pressure

`\large {\boxed {\bold {Kp ~ = ~ \frac {[pC] ^ m [pD] ^ n} {[pA] ^ p [pB] ^ q}}}}`

The value of Kp and Kc can be linked to the formula '

`\large {\boxed {\bold {Kp ~ = ~ Kc. (R.T) ^ {\Delta n}}}}`

R = gas constant = 0.0821 L.atm / mol.K

Δn=moles products - moles reactants or

number of product coefficients-number of reactant coefficients

For reaction :

A(g) ⇌ C(g)+B(g)

number of product coefficients = 1+1=2

number of reactant coefficients = 1

Δn= 2 - 1 =1

So Kp/Kc = RT