Textbook 5G.21

[Jessie Hsu 1C]

5G.21 Calculate the equilibrium constant at 25 °C for each of the following reactions, by using data in Appendix 2A:

(a) the combustion of hydrogen: 2H2(g) + O2(g) ⇌2 H2O(g)
(b) the oxidation of carbon monoxide: 2 CO(g) +O2(g)⇌2 CO2(g)
(c) the decomposition of limestone: CaCO3(s)⇌CaO(s) + CO2(g)

Can someone show me how to approach this question? I used the Van't Hoff equation but somehow my value is much smaller than what the answer key shows.

[Mohamed Mido]

the answer you got was probably just lnK. to get K by itself you apply the rule e^lnK, which should give you the correct answer

[Aayushi Jani 3A]

You would first have to calculate delta Gr, using the delta Gf values found in the appendix. Then, you would plug that into the equation delta Gr = -RTlnK. Remember, in order to find K, you would have to do e^-(Gr/RT).

[Irene Chang 2F]

I rewrote the equation to be lnK = deltaGr/-RT, when deltaGr is products - reactants value from appendix A. Then I did e^lnK to get my K value.