Name----------------------------------------------Date---------------------period---------------
Hess’s Law of Summation
1.
B2H6(g) + 6 Cl2(g)
BCl3(g) + 3 H2O(l)
H3BO3(g) + 3 HCl(g)
B2H6(g) + 6 H2O(l)
2 H3BO3(s) + 6 H2(g)
1/2 H2(g) + 1/2 Cl2(g)
HCl(g)
2. 2 OF2(g) + 2 S(s)
OF2(g) + H2O(l)
O2(g) + 2 HF(g)
SF4(g) + 2 H2O(l)
4 HF(g) + SO2(g)
S(s) + O2(g)
SO2(g)
2 BCl3(g) + 6 HCl(g)
Ho=?
Ho= -112.5 kJ/rx
Ho= -493.4 kJ/rx
Ho= -92.3 kJ/rx
SO2(g) + SF4(g)
Ho=?
Ho= -276.6 kJ/rx
Ho= -827.5 kJ/rx
Ho= -296.9 kJ/rx
3. N2H4(l) + 2 H2O2(l)
N2(g) + 4 H2O(l)
Ho = -622.3 kJ/rx
Ho= -285.8 kJ/rx
Ho= -187.8 kJ/rx
N2H4(l) + O2(g)
N2(g) + 2 H2O(l)
H2(g) + 1/2 O2(g)
H2O(l)
H2(g) + O2(g)
H2O2(l)
4. P4O10(g) + 6 PCl5(g)
1/4 P4(s) + 3/2 Cl2(g)
PCl3(g)
P4(s) + 5 O2(g)
P4O10(g)
PCl3(g) + Cl2(g)
PCl5(g)
PCl3(g) + 1/2 O2(g)
Cl3PO(g)
:
Ho=?
10 Cl3PO(g)
Ho=?
Ho= -306.4 kJ/rx
Ho= -2967.3 kJ/rx
Ho = -84.2 kJ/rx
Ho= -285.7 kJ/rx
5. 2 SO2(g) + 2 P(s) + 5 Cl2(g)
SOCl2(l) + H2O(l)
SO2(g) + 2 HCl(g)
PCl3(l) + 1/2 O2(g)
POCl3(l)
P(s) + 3/2 Cl2(g)
PCl3(l)
4 HCl(g) + O2(g)
2 Cl2(g) + 2 H2O(l)
6. C3H8(g) + 5 O2(g)
3 C(s) + 4 H2(g)
C3H8(g)
C(s) + O2(g)
CO2(g)
H2(g) + 1/2 O2(g)
H2O(g)
2 SOCl2(l) + 2 POCl3(l)
DHo = +10.3 kJ/rx
Ho= -325.7 kJ/rx
DHo = -306.7 kJ/rx
Ho= -202.6 kJ/rx
3 CO2(g) + 4 H2O(g)
Ho=?
Ho= -103.8 kJ/rx
Ho= -393.5 kJ/rx
Ho = -241.8 kJ/rx
7. 2 N2(g) + 5 O2(g)
2 N2O5(g)
Ho= -571.6 kJ/rx
Ho= -73.7 kJ/rx
Ho= -348.2 kJ/rx
2 H2(g) + O2(g)
2 H2O(l)
N2O5(g) + H2O(l)
2 HNO3(l)
N2(g) + 3 O2(g) + H2(g)
2 HNO3(l)
8. C(s) + 2 H2(g)
C(s) + O2(g)
CO2(g)
H2(g) + 1/2 O2(g)
H2O(l)
CO2(g) + 2 H2O(l)
CH4(g) + 2 O2(g)
Ho=?
CH4(g)
Ho=?
DHo = -393.5 kJ/rx
DHo= -285.8 kJ/rx
Ho= +890.3 kJ/rx