Covalent bonds are in the air you breathe and the water you drink. how are covalent bonds formed?

8.98 dm3 of hydrogen gas is collected at 38.8 °c. find the volume the gas will occupy at -39.9 °c if the pressure remains constant.

40dm3 of gas at 760 torr are heated from 5°c to 50°c what is the new volume

A5 mole sample of liquid acetone is converted to a gas at 75.0°c. if 628 j are required to raise the temperature of the liquid to the boiling point, 15.600 kj are required to evaporate the liquid, and 712 j are required to raise the final temperature to 75.0°c, what is the total energy required for the conversion?