What property of matter can be observed using a pan of water?

What effect does a decrease in temperature have on the overall rate of a chemical reaction? a decrease in temperature decreases . the reaction rate will

As air becomes more dense, (select all that apply) o. air weighs less o. gas molecules are closer together o. air is colder o. air weighs more o. gas molecules are further apart o. air is hotter

If anyone would be able to me out with these three questions it would be these are from the chem 2202 course.