Rates can be calculated with Arrhenius equation k = Axe^(-Ea/RT)
a. temperature affects the rate - imagine you are making coffee, so coffee crystals are boiled faster on higher temperature. Simplified but makes sense.
b. Ea is activation energy. Imagine, while preparing coffee, some of ingredients change to a different one, so there is a A -> B reaction (simplified). Now, Ea is energy barrier that stands on the arrow of this reaction, preventing A to transform to B. If Ea is small, reaction will go easy (not fast!), if Ea is large –reaction will not happen so easy (you ll have to use catalyst for example)
