Rates of reactions

— to control the yield

Finding the rate of reaction

— amount of product produced per unit of time

— amount of reactant used up per unit of time

Finding volume of gas produced in a reaction

— gas syringe has less friction

— reaction is timed

— volume / time

How to increase the rate of a reaction

— increase the concentration

• more particles → more collisions

— increase the temperature

• more heat energy → faster moving particles → more collisions

— increase the surface area

• more atoms exposed in the reaction → more collisions

— add a catalyst

• speeds up the entire reaction
• cannot be used in all reactions

Catalysts

— a substance that speeds up a chemical reaction, without being chemically changed itself

e.g. decompostition of hydrogen peroxide

2H2O2 (l) → 2H2O (l) + O2 (g) MANGANESE IS A CATALYST

Enzymes

— proteins made by cells to act as a biological catalyst

e.g. catalase (liver) → help break down H2O2 in the body (harmful)

amylase (saliva) → help break down starch molecules

reactions → collision + energy

catalysts → helps the collision require less energy