Amixture from which some of the particles settle out slowly upon standing

Iknow #2 is d. i just need to know why

What determines the average kinetic energy of the particles in a gas? a. the number of collisions b. the number of particles c. the size of the particles d. the temperature

Which of the following is an example of physical change not a chemical change? a) a log gives off heat and light as it burns. b) a tree stores energy from the sun in its fruit. c) a penny lost in the grass slowly changes color. d) a water pipe freezes and cracks on a cold night.