What are 4 things that you can change in order to speed up or slow down a chemical reaction?

1. Temperature: Depending on the temperature of the reactants, the reaction rate will differ. The higher the temperature (or the hotter the reactant is), the quicker the reaction will occur. The cooler the reactant is, the longer it will take for a reaction to take place. The heat causes the particles to move quickly, and due to the Collision Theory, which states that in order for a reaction to occur, molecules must collide, the particles will be more likely to bump into each other, and so the reaction will occur faster.

2. Concentration: The higher the concentration of a reactant, the quicker the reaction will occur. This means that there are more particles of that particular substance, meaning it will collide more frequently into the particles of the other reactant. This increases the reactant rate because the more concentrated a reactant is, it means that the less space there is between the two reactants.

3. Surface Area: Basically, the more particles that are exposed during the experiment, the faster the reaction will occur. The more the particles are exposed, the faster it is for the other reactant to collide into the particles, meaning the reaction rate will increase.

4. Catalysts: Catalysts are substances that increase the rate of reaction by speeding up the reaction without being used up in the reaction. It does not affect the reactants in any other way than making them collide into each other more frequently, and it doesn't affect the product (or products) produced