Which equation represents a physical change?
(1) h2o(s) + 6.01 kj ==> h2o(l)
(2) 2h2(g) + o2(g) ==> 2h2o(g) + 483.6 kj
(3) h2(g) + i2(g) + 53.0 kj ==> 2hi(g)
(4) n2(g) + 2o2(g) + 66.4 kj ==> 2no2(g)

The answer would be number one because notice the states of all the other answers. The numbers 2-4 are all adding energy to a gas and the products end up in the gas state as well which denotes no change in physical state. However if you look at number one it also has energy added but the reactant is originally a solid while the product is a liquid. Example- (s)= solid (l)= liquid (g)= gas

If the water vapor content stays the same and the temperature drops, then the relative humidity increases. its vise versa.if the water vapor content stats the same and the temperature rises, the relative humidity decreases. so, yes, i'd say that temperature and humidity have a strong relationship.