The Collision Theory explains how chemical reactions occur and why reaction rates differ for different reactions. This theory is based on the idea that reactant particles must collide for a reaction to occur, but only a certain fraction of the total collisions have the energy to connect effectively and cause the reactants to transform into products.

This is because only a portion of the molecules have enough energy and the right angle at the moment of impact to break any existing bonds and form new ones!

If you increase the temperature in the experiment the rate of the reaction increases for example, for many reactions happening at room temperature, the rate of reaction doubles for every 10 degrees rise in temperature, this means the rate can be quadrupled if the temperature is raised by 20 degrees.

If you add a catalyst it is not consumed in the reaction, it merely speeds up the reaction by providing a lower energy path between reactants and products.
If you increase surface area the reaction happens faster because the molecules have more sides to bounce off and react with.