2. b, contraction because work is done on the system, so the change in volume is negative (less than zero)
3 Energy is neither created nor destroyed, it can change forms.
4. c, energy is required to break apart solid ice
5. -6.86 KJ
6. -565 KJ
7. -522.1 KJ, 522 KJ would be released when 20g of aluminum was reacted with excess chlorine
8. 303 degrees C