Chemical Changes and Reactions Overview

Chemical change

Matter transformation producing new substances.

Formation of new substances

Creation of products like precipitates or gas bubbles.

Precipitate

Solid formed from a solution during a reaction.

Endothermic change

Energy absorbed, e.g., ice melting.

Exothermic change

Energy released, e.g., combustion.

Reactants

Elements mixed in a chemical equation.

Products

Elements formed from reactants in a reaction.

Conservation of mass

Matter is neither created nor destroyed.

Open system

Matter can enter or escape during reactions.

Closed system

Matter cannot enter or escape during reactions.

Balanced chemical equation

Equal number of atoms on both sides.

Synthesis reaction

Two substances combine to form one product.

Decomposition reaction

One substance breaks into two or more products.

Single replacement reaction

One element replaces another in a compound.

Double replacement reaction

Ions of two compounds exchange places.

Activation energy

Minimum energy to initiate a chemical reaction.

Concentration

Amount of substance in a specific volume.

Catalyst

Material that lowers activation energy, speeding reactions.

Enzymes

Biological catalysts that facilitate cellular reactions.

Inhibitor

Material that slows down a chemical reaction.

Combustion

Rapid reaction of oxygen with fuel, producing heat.

Fire triangle

Essential elements: fuel, oxygen, and heat.

chemical property

A characteristic of a pure substance that describes its ability to change into different substances

physical property

A characteristic of a pure substance that can be observed without changing it into another substance

physical change

a change of matter from one form to another without a change in chemical properties

matter

Anything that has mass and takes up space

chemistry

The study of the properties of matter and how matter changes