Question 1
The heat of combustion per mole for acetylene, C
2H
2(
g), is -1299.5 kJ/mol. Assuming that the combustion products are CO
2(
g) and H
2O(
l), and given that the enthalpy of formation is -393.5 kJ/mol for CO
2(
g) and -285.8 kJ/mol for H
2O(
l), find the enthalpy of formation of C
2H
2(
g).
◦ -226.7 kJ/mol
◦ -846.1 kJ/mol
◦ -620.2 kJ/mol
◦ +226.7 kJ/mol
Question 2
Which of CH
4(
g), C
2H
2(
g), and CH
3OH(
l) provides the most energy per gram upon combustion and which provides the least?
| CH4(g) + 2 O2(g) → CO2(g) + 2 H2O(l) | ΔH° = -890 kJ |
| 2 C2H2(g) + 5 O2(g) → 4 CO2(g) + 2 H2O(l) | ΔH° = -2599 kJ |
| 2 CH3OH(l) + 3 O2(g) → 2 CO2(g) + 4 H2O(l) | ΔH° = -1453 kJ |
◦ C
2H
2 provides the most energy per gram and CH
3OH the least.
◦ CH
4 provides the most energy per gram and C
2H
2 the least.
◦ CH
4 provides the most energy per gram and CH
3OH the least.
◦ C
2H
2 provides the most energy per gram and CH
4 the least.
Basic energy of a human life
Carbon dioxide emission per gigajoule of energy released
Historical U.S. Energy Use
Performing a Gram Stain
Activation energy
Ecosystem Energy Flow and Efficiency