How are weight and mass related? what happens to the other if you change one of them?

mass and weight are closely related because mass affects the weight of an object experiencing the effects of gravity. weight is the measure of the force of gravity on an objects's mass, while mass is the measure of how much matter there is in an object.

it provides an alternative energy pathway for the reaction to proceed.

a catalyst is a substance that speeds up the rate of a chemical reaction but is not consumed during the course of the reaction.

catalysts increase the rate of reaction without being used up. they do this by lowering the activation energy needed. with a catalyst, more collisions result in a reaction, so the rate of reaction increases. different reactions need different catalysts.

a catalyst works by providing an alternative reaction pathway to the reaction product. the rate of the reaction is increased as this alternative route has a lower activation energy than the reaction route not mediated by the catalyst.