7 - Unit 2, Section 1 - Day 1

Chemical Reactions - A Review

Unit 2, Section 1

Categorize

Options (6)

Melting Wax

Freezing Water

Dissolving Salt

Burning A Match

Using a Glowstick

Frying an Egg

Categorize each of the following changes as either a physical change or a chemical change.

Physical Change

Chemical Change

Chemical Reaction - a change in the identity of a substance

• New substances are formed during a chemical reaction

Chemical Reactions

Chemical Bond - the force that holds two atoms together in a molecule

• In a chemical reaction, old chemical bonds break and new chemical bonds form

How Chemical Reactions Happen

• Reactant - a starting material in a chemical reaction

• Product - an ending material in a chemical reaction

• "Reactants form products"

Reactants and Products

Chemical equations are used to describe chemical reactions

• Reactants are on the left side of the equation

• Products are on the right side of the equation

• An arrow separates them and shows a reaction has occurred

Chemical Equations

How To Read a Chemical Equation

​C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O

​"One molecule of C₆H₁₂O₆ plus six molecules of O₂ react to form six molecules of CO₂ and six molecules of H₂O"