3.2. hw: how much heat is needed to vaporize 150. g of benzene?

3.1 HW. A gas in a cylinder of an engine expands by 500.0 mL against a pressure of 1.20 atm. How much work is done?

3.2. HW: How much heat is needed to vaporize 150. g of benzene?

The boiling point of benzene is 80o C.

The Hvapo (benzene) is 30.8 kJ/mol.

3.3. HW:NaOH + HCl H2O + NaCl

50.0 mL of 1.0 M NaOH is mixed with 50.0 mL of 1.0 M HCl at 25.0 oC. The temperature of the solution increases to 31.9 oC. What is the total heat released? How much energy is released per mol of reactant? What is the enthalpy (H) for the reaction?

3.4. HW:SO2(g) + O2(g) SO3(g)

2.00 mols SO2 are reacted with 1.00 mol O2 at 25o C and 1.00 atm. 198 kJ of energy is released as heat. Calculate H and E.

3.5. HW:4Al(s) + 3O2(g) 2Al2O3(s) Hrxn = -3352 kJ/mol rxn

How much heat is released upon reaction of 24.2 g Al at 25o C and 1 atm?

3.6. HW:CuSO4(aq) + 2NaOH(aq) Cu(OH)2(s) + Na2SO4(aq)

50.00 mL of 0.400 M CuSO4 reacts with 50.00 mL of 0.600 M NaOH at 1 atm. The total heat evolved is 1.49 kJ. What is Hrxn?

3.7. HW:Hess’s Law: another exampleFind Hrxn

o for:

C(gr) + 2H2(g) CH4(g)

- - - - - - - - - - - - - - - - - - - - - - - - - - - -CH4(g) + 2O2(g) CO2(g) + 2H2O(l) -890.3 kJ

Standard enthalpies of formations:

C(gr) + O2(g) CO2(g) -393.5 kJ

H2(g) + ½O2(g) H2O(l) -285.8 kJ

3.8. HW:2 NH2CH2COOH (s) + 3O2(g)

H2NCONH2(s) + 3CO2 (g) + 3H2O(l)

What is the standard enthalpy of reaction?

What is the enthalpy per mol of NH2CH2COOH (glycine reactant)?