all 4 questions please

pH=4.5 2. Explain the terms: saturated, unsaturated and supersaturated solutions. 4. Using the kinetic molecular theory, answer each of the following questions. a. What does it mean when we say that the pressure of a gas has increased? b. What does it mean when we say that the temperature of gas has decreased? 3. Popcorn pops as the water in the kernel is vaporized. The building pressure becomes too much for the shell of the kernel and it explodes. Explain, using your knowledge of the behavior of gases, what happens to the temperature just before and just after the kernel pops. 4. Explain each of the following observations: (a) Metals expand when heated, yet contracted in cold weather. (b) A certain amount of moles of water occupies much more space as a gas than as a liquid