What energy changes occur when chemical bonds are formed and broken?
A. Energy is absorbed when bonds are formed and when they are broken.
B. Energy is released when bonds are formed and when they are broken.
C. Energy is absorbed when bonds are formed and released when they are broken.
D. Energy is released when bonds are formed and absorbed when they are broken.

The temperature of a 2.0 g sample of aluminium increases from 25°C to 30°C. How many joules of heat energy were added? (Specific heat of Al = 0.90 J g–1K–1)
A. 0.36
B. 2.3
C. 9.0
D. 11