Why doe gasses dissolve in colder temperatures

Gas molecules tend to fly around and bump into each other. If you add heat to a gas, which is in a ballon, the volume of the balloon increases because gases expand when you heat them. As you add the heat, the gas molecules move faster and collide with more force. Solids, on the other hand, are in relatively fixed position.

Say you have a pot of boiling water with the lid on, water molecules are constantly being shot out of the liquid and being shot back into it. The amount the leaves and enters depends on pressure, temperature, and volume of the container. The more heat inside the water, the faster the water molecules will shoot out.

A hot gas in a liquid will have a lot of energy and be able to escape the liquid, but a colder gas will have less energy to escape and be more likely to remain in the liquid making it more soluble.

The atoms in solids are in fixed positions and bound together by either ionic or covalent bonding. Let's assume the liquid in this case is water and the dissolvable substance is salt, which has ionic bonds. When you had heat to water the molecules will move faster and with more energy. Water molecules with more kinetic energy will slam into salt particles with more energy which allows it to break apart the salt particles with more ease. Simply imagine throwing a baseball really fast, then really slow, at a LEGO structure. The faster you throw the baseball, the farther the LEGOs will fly.

Exothermic,  physical change after it is already baked