When the temperature is cold tim's tires look under inflated

This a sign of decrease in pressure, the pressure of the air molecules inside the tire has reduce due to the decrease in the temperature.  This is to satisfy the pressure law which states that pressure of a fixed mass of a gas at a constant volume is proportional to the absolute temperature .

explain what happens when a helium-filled balloon is released and rises into the atmosphere

It may burst or increase in size depending on the amount of pressure available, at higher elevation, the pressure is low , therefore the volume must rise to satisfy the boyle’s law.

How does kinetic energy of particles vary with temperature.

Temperature is proportional to the kinetic energy , the higher the temperature the higher the kinetic energy and the lower the temperature the lower the kinetic energy. In fact temperature is the measure of the average kinetic energy of gases

Explain why a balloon expands when taken to a higher elevation if the temperature remains constant.

When a balloon is taken to higher elevation, the volume will increase, at higher elevation , the pressure is lower, the volume which now the filled balloon will increase in size. This because according to boyle’s law the pressure of a fixed mass of a gas, at constant temperature is inversely proportional to the volume.

What assumption of the kinetic molecular theory explains why a gas can expand to fill a container

·       The volume of a gas is negligible compared to the volume of their container.

·       Gases moves in all direction colliding with one another and with the hall of the container

What assumption of the kinetic molecular theory explains why a gas can expand to fill a container

Gases do not have fixed shape and volume their volume is the volume of their container.