Question

Write an equilibrium constant expression, Kp, based on the formation of one mole of each of the following gaseous compounds from its elements at 25 °C. (a) NO(g) (b) NH3(g) (c) NOCl(g)

Answer 1

To find:

Equilibrium constant K_(p) for the formation of

• NO
• NH3
• NOCl

Calculation:

1) $\bold{N_{2}+O_{2}\rightarrow 2NO}$.

$\therefore \: K_{c} = \dfrac{ { \{ NO\}}^{2} }{ \{N_{2} \} \{ O_{2} \} }$

$\therefore K_{p} = K_{c} × {RT}^{\Delta n}$

$=> K_{p} = K_{c} × {RT}^{(2-1-1)}$

$=> K_{p} = K_{c} × {RT}^{0}$

$=> K_{p} = K_{c} × 1$

$\boxed{ = > \: K_{p} = \dfrac{ { \{ NO\}}^{2} }{ \{N_{2} \} \{ O_{2} \} } }$

2) $\bold{N_{2}+3H_{2}\rightarrow 2NH_{3}}$

$\therefore \: K_{c} = \dfrac{ { \{NH_{3} \}}^{2} }{ \{N_{2} \} { \{H_{2} \}}^{3} }$

$\therefore K_{p} = K_{c} × {RT}^{\Delta n}$

$=> K_{p} = K_{c} × {RT}^{(2-1-3)}$

$=> K_{p} = K_{c} × {RT}^{(-2)}$

$\boxed{ = > \: K_{p} = \dfrac{ { \{NH_{3} \}}^{2} }{ \{N_{2} \} { \{H_{2} \}}^{3} } \times {(RT)}^{ - 2} }$

3) $\bold{N_{2}+O_{2}+Cl_{2}\rightarrow 2NOCl}$

$\therefore \: K_{c} = \dfrac{ { \{NOCl\}}^{2} }{ \{N_{2} \} \{O_{2} \} \{ Cl_{2}\}}$

$\therefore K_{p} = K_{c} × {RT}^{\Delta n}$

$=> K_{p} = K_{c} × {RT}^{(2-1-1-1)}$

$=> K_{p} = K_{c} × {RT}^{(-1)}$

$\boxed{ = > \: K_{p} = \dfrac{ { \{NOCl\}}^{2} }{ \{N_{2} \} \{O_{2} \} \{ Cl_{2}\}} \times {(RT)}^{ - 1} }$

Hope It Helps.