As the temperature of a gas is increased, the average kinetic
energy of its molecules

Increases.

Explanation:

Temperature is the measure of the average kinetic energy of a system. As temperature increases, so will kinetic energy. As kinetic energy increases, speed increases.

Kerosene is lighter than water and so it floats on the water and continues to burn. Carbon (IV) oxide blankets the flame cutting off the supply of oxygen and extinguishing the fire.

Explanation:

As water is heavier than kerosene, it slips down permitting the kerosene to rise to the surface and continue to burn. Besides, the existing temperature is so high that the water poured on the fire would evaporate before it can extinguish the fire. Thus the kerosene fire cannot be extinguished with water.