Write the equilibrium constant expression for each of the following reactions.
a. C(s) + CO2(g) = 2 CO(g)
b. 2 C2H6(g) + 7 O2(g) = 6 H2O(g) +4 CO2 (g)
c. CaO(s) + SO3 (g) = CaSO4 (s)

Dumbledore decides to gives a surprise demonstration. he starts with a hydrate of na2co3 which has a mass of 4.31 g before heating. after he heats it he finds the mass of the anhydrous compound is found to be 3.22 g. he asks everyone in class to determine the integer x in the hydrate: na2co3·xh2o; you should do this also. round your answer to the nearest integ