Factors Affecting Rates of Chemical Reactions Created by: Mrs. Dube Factors Affecting Rates of Chemical Reactions

Chemical Reactions (copy into notes) A chemical reaction produces new substances by changing the way in which the atoms are arranged New arrangements of atoms form different substances

Reactants and Products(copy into notes) Reactants are the substances present at the beginning of a chemical reaction Products are the substances formed by a chemical reaction present at the end of a chemical reaction

Evidence of Chemical Reactions (copy into notes) Color change Formation of a precipitate (a solid product) Formation of a gas (sometimes seen as bubbles) Temperature change

Quick Check for Understanding How do reactants differ from products? How can you tell that a chemical reaction has occurred? (Restate the question and answer in your notes)

Rates of Chemical Reactions (copy into notes) Rates of chemical reactions can vary Many factors affect reaction rates such as: concentration, surface area, temperature, and the presence of a catalyst

Concentration Concentration measures the number of particles present in a certain volume A high concentration of reactants means that there is a large number of particles that collide and react during a chemical reaction (Copy into notes)

Surface Area Surface area affects the rate of chemical reactions Breaking a large piece of material into smaller parts increases the surface area of the material which increases the reaction rate (Copy into notes)

Temperature Reaction rate can be increased by making the particles move faster Faster moving particles have more collisions with greater force Adding energy to the reactants raises the temperature and causes reaction rate to increase (Copy into notes)

Catalysts A catalyst is a substance that increases the rate of the chemical reaction but is not consumed in the chemical reaction (Copy into notes)

Quick Check for Understanding What factors impact reaction rate? How does surface area affect the rate of a reaction? What is a catalyst? (Restate the question and answer in your notes)