CHEM 1050 Chapter Notes - Chapter 6: Molar Mass, Enthalpy, Conversion Of Units

• School: University of Guelph
• Department: Chemistry
• Course: CHEM 1050
• Professor: Richard Delaat

Document Summary

Thermochemical equation: the chemical equation for a reaction (including phase labels) in which the equation is given a molar interpretation, and the enthalpy of reaction for these molar amounts is written directly after the equation. It is i(cid:373)po(cid:396)ta(cid:374)t to (cid:449)(cid:396)ite states (cid:271)e(cid:272)ause h depe(cid:374)ds o(cid:374) the phase of the su(cid:271)sta(cid:374)(cid:272)e: 2h2(g) + o2(g) 2h2o(g); h = -483. 7kj, 2h2(g) + o2(g) 2h2o(l); h = -571. 7kj. 6. 5 applying stoichiometry to heats of reaction. The quantity of heat obtained from a reaction will depend on the amount of reactants. To calculate the heat obtained (either absorbed or evolved), use the following conversion: Conversion factor: g a to mol a (using molar mass) Conversion factor: mol a to kj (using enthalpy of rxn) Example: ch4(g) + 2o2(g) co2(g) + 2h2o(cid:894)l(cid:895); h = -890. 3kj where there are 10g of ch4 g ch4 mol ch4 kj heat. 10 g ch4 x 1 mol ch4 x -890. 9 kj = -556 kj.