I need help with this chemistry Escape room.

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.

If 3 moles of a compound use 24 j of energy in a reaction, what is the a hreaction in j/mol?

How many liters of ethylene glycol antifreeze (c2h6o2), with a density of 1.100 g/l, would you add to your car radiator containing 15.0 kg of water if you needed to protect your engine to - 21.5°c? for water, kf = 1.86°c m -1.