Physical and chemical change

What is a physical change?

A change in its ohysical form but not its chemical composition.

What is a chemical change?

A change in matter that produces one or more new substances

What does the law of conservation of mass state?

mass cannot be created or destroyed

What are reactants?

Chemicals that react together during a reaction

What is a chemical reaction?

process that changes one set of chemicals into another set of chemicals

What are exothermic reactions?

chemical reactions that release energy in the form of heat, light, or sound

What are endothermic reactions?

reactions that absorb energy

How do chemical reactions occur?

When particles in the reactants collide

What is the collision theory?

The theory that chemical reactions only occur when particles collide with sufficient energy

What is activation energy?

minimum energy needed to start a reaction

Factors that affect the rate of a reaction

Temperature, surface area, concentration, catalyst

How does temperature affect the rate of reaction?

The higher the temperature the faster the reaction

How does surface area affect the rate of reaction?

The more surface area, the faster the reaction, because there's more room for collisions

How does concentration affect the rate of reaction?

At higher concentrations, there are more particles in a smaller space so there are more successful collisions

How does a catalyst affect the rate of reaction?

A catalyst is a substance that speeds up a chemical reaction without being consumed. It works by providing an alternative pathway for the reaction that requires less energy, making the reaction occur more quickly.

What is an energy profile diagram?

A diagram showing the energy change in a chemical reaction