2NO2(g) ⇌ N2O4(g) K = 1.15 NO2 0.650 mol/L

2NO2(g) ⇌ N2O4(g) K = 1.15 NO2 0.650 mol/L

 

 

In a sealed container,

nitrogen dioxide is in equilibrium with dinitrogen tetroxide.

2NO2(g) ⇌ N2O4(g) ... K = 1.15 at 55°C

Find the equilibrium concentrations

of nitrogen dioxide and dinitrogen tetroxide

if the initial concentration of nitrogen dioxide is 0.650 mol/L.

 

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ICE 도표를 작성하면,

 

 

 

 

............. 2NO2(g) . ⇌ . N2O4(g)

초기(M) . 0.650 ............. 0

변화(M) . –2x ................ +x

평형(M) . 0.650–2x ....... x

 

K = [N2O4] / [NO2]^2

( 참고: 평형상수식 https://ywpop.tistory.com/7136 )

 

 

 

1.15 = (x) / (0.650–2x)^2

 

(1.15)(0.650^2) – (1.15)(2)(0.650)(2x) + (1.15)(2x)^2 = x

 

4.6x^2 – 3.99x + 0.485875 = 0

 

 

 

근의 공식으로 x를 계산하면,

( 참고 https://ywpop.tistory.com/3302 )

 

x = 0.1465 M

 

 

 

[NO2] = 0.650 – 2x

= 0.650 – 2(0.1465)

= 0.357 M

 

 

 

[N2O4] = 0.1465 M

≒ 0.147 M

 

 

 

 

[검산]

K = [N2O4] / [NO2]^2

= [0.1465] / [0.357]^2

= 1.149

≒ 1.15