Unformatted text preview: 1. To measure the enthalpy change, 5.2g of H2SO4 (l) were added (with stirring) to 135g
of water in a coffee cup calorimeter. This resulted in an increase in temperature from
20.2oC to 28.8oC. Calculate the enthalpy change for the process, in units of kJ per
mole of sulfuric acid. 2. Enthalpy changes (H0) for the following reactions can be determined experimentally:
N2(g) + 3H2(g ) 2NH3(aq)
4NH3(g) + 5O2(g) 4NO2(g) + 6H2O(g)
H2(g) + 1/2O2(g) H2O(g) H0 = -138.4kJ
H0 = -114.0kJ
H0 = -1169.6kJ However the standard enthalpy change (Hfo) for formation of NO
cannot be determined experimentally. Use the H0 values given above to determine
Hfo for NO. 3. Calculate the Hfo (in kJ per mole) for benzene, C6H6, from the following data:
2C6H6(l ) + 15O2(g)
12CO2(g ) + 6H2O(g) Ho (C6H6) = -6534 kJ/mol
Hfo (CO2) = -393.5 kJ/mol
Hfo (H2O) = -285.8 kJ/mol
Hfo (C6H6) = -393.5 kJ/mol
4. Vinyl chloride (H2C=CHCl), is prepared by a two-step process that begins with the
reaction of Cl2 with ethylene (H2C=CH2) to produce 1,2-dichloroethane.
Cl2(g) + H2C=CH2(g) ClCH2CH2(l )
H = -217.5 kJ/mol
S = -233.9 J/mol K (a) Tell whether the reaction is favored by entropy only, enthalpy only, by both
enthalpy and entropy or neither.
(b) Calculate G at 298K.
(c) At what temperature will this reaction be at equilibrium? ...
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