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awuah29
12-09-2005, 07:48 PM
Heh, Anyone here knows how to work those problems. I have all the answers, but somehow don't know how to et it up. Thanks

4. Given that:
S(s) + O2(g) --> SO2(g); DH = -296.8 kJ/mol
2 SO3(g) --> 2 SO2(g) + O2(g); DH = +197.8 kJ/mol

Determine the enthalpy change of the reaction: 2 S(s) + 3 O2(g) --> 2 SO3(g) a) -99 kJ/mol
b) 99 kJ/mol
c) 495 kJ/mol
d) -495 kJ/mol
e) -791.4 kJ/mol

7. From the following data at 25°C:
H2(g) + Cl2 ---> 2 HCl(g); DH° = -185 kJ
2 H2(g) + O2(g) ---> 2 H2O(g); DH° = -483.7 kJ
Calculate DH° at 25° for the reaction below:

4 HCl(g) + O2(g) ---> 2 Cl2(g) + 2 H2O(g)
a) +114 kJ
b) +299 kJ
c) -299 kJ
d) -114 kJ
e) -86.8 kJ

awuah29
12-10-2005, 02:22 AM
anyone out there who can help me with those problemes?

Holden_Caulfield
12-11-2005, 12:50 AM
Heh, Anyone here knows how to work those problems. I have all the answers, but somehow don't know how to et it up. Thanks

4. Given that:
S(s) + O2(g) --> SO2(g); DH = -296.8 kJ/mol
2 SO3(g) --> 2 SO2(g) + O2(g); DH = +197.8 kJ/mol

Determine the enthalpy change of the reaction: 2 S(s) + 3 O2(g) --> 2 SO3(g) a) -99 kJ/mol
b) 99 kJ/mol
c) 495 kJ/mol
d) -495 kJ/mol
e) -791.4 kJ/mol

dH=(2*(-296.8))-99=-791.4kJ

7. From the following data at 25°C:
H2(g) + Cl2 ---> 2 HCl(g); DH° = -185 kJ
2 H2(g) + O2(g) ---> 2 H2O(g); DH° = -483.7 kJ
Calculate DH° at 25° for the reaction below:

4 HCl(g) + O2(g) ---> 2 Cl2(g) + 2 H2O(g)
a) +114 kJ
b) +299 kJ
c) -299 kJ
d) -114 kJ
e) -86.8 kJ
-483.7-2*(-185)~114kJ