CHM135H1 Lecture 26: 14/11/16 CHM135H1 F LEC0101 Lecture 26 Notes

• School: UTSG
• Department: Chemistry
• Course: CHM135H1
• Professor: Jeremy Schofield

Document Summary

Chm135h1 f - lecture 26 - chapter 9 (3) Standard state: stablest form of 1 m substance at pressure of 1 atmospheres and a specified temperature (usu. C3h8(g) + 5o2(g) 3co2(g) + 4h2o(g) (cid:474)h = 2044 kj. C3h8(g) + 5o2(g) 3co2(g) + 4h2o(l) (cid:474)h = 2220 kj. 2al(s) + fe2o3(s) 2fe(s) + al2o3(s) (cid:474)h = 852 kj exothermic. 2fe(s) + al2o3(s) 2al(s) + fe2o3(s) (cid:474)h = +852 kj endothermic. Elementary steps of reaction unimportant as h of reaction is a state function. R i h = h. I p h = h. R p h = h. Can define standard reaction enthalpy as decomposition of reactant into constituent elements. Reactants products rxnh= h f (reactants) - h f (reactants) In a balanced chemical equation, mass of each element in reactants and products is equal. H f (a) is enthalpy (heat at constant pressure) of formation per of compound a, per mole.