Question #162694

Automobiles and trucks pollute the air with NO. At 2000.0°C, Kc for the reaction N2(g)+O2(g)⇌2NO(g) At 2000.0°C Kc = 4.100 × 10–4 and ΔH° = 180.6 kJ. What is the value of Kc at 31.00°C?

Expert's answer

Use Van't Hoff equation

"ln\\frac{K_2}{K_1}=\\frac{-\\Delta H}{R}(\\frac{1}{T_2}-\\frac{1}{T_1})"

"T_1(K)= 2000.0 + 273= 2273 K"

"T_2(K) = 31.00+273=304.K"

"\\Delta H = 180.6 kJ = 180600J"

"K_1 = 4.100\\times10^{-4}"

"K_2 - ?"

"ln\\frac{K_2}{4.100\\times 10^{-4}}= \\frac {-180600}{8.314}(\\frac{1}{304}-\\frac{1}{2273})"

"K_2 = 1.886\\times10^{-26}"

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