Here are some thermochemistry problems I'm confused about:?

Question

1 Given the following thermochemical equation:
2Fe2O3+3C=>4Fe+3CO2 q= -2310KJ
If a reaction has a heat change of -328KJ, what quantity of Fe2O3 in moles reacted?

2 Given the following thermochemical equation:
FeS+2HCl=>FeCl2+H2S q= -1230KJ
What is the heat change in KJ accompanying the production of 1.43moles of H2S?

3Given the following thermochemical equation:
4C2H3O2Br+3O2=>8CO+6H2O+2Br2 q= 2910KJ
What is the heat change in KJ accompanying the production of 13.8grams of H2O?

Answer 1

Just follow the bouncing ball. In problem 1, the equation indicates that 2 moles of ferric oxide lead to production of -2310 KJ. By proportion: (heat change/moles)
-2310 / 2 = -328 / X and X = 0.284 moles

Same deal in problem 2 except that 1 mole of H2S produced leads to -1230 KJ. By proportion
-1230/1 = Y /1.43, Y = -1760 KJ

Same deal in problem 3, but we have to convert the grams of H2O to moles. The equation says 6 moles of H2O are produced with 2910 KJ. MW of water is 18, so 13.8 grams is .767 moles. By proportion
2910/6 = Z /0.767 and Z= 372 KJ