Western Civ Test

Reactants

The original substances in a chemical equation, located on the left side.

Products

The new substances that are created in a chemical reaction, located on the right side.

Law of Conservation of Matter

Matter cannot be created nor destroyed; it shows that the number of atoms must be the same on both sides of a balanced equation.

Coefficient

A number in front of a chemical formula indicating how many molecules of a substance are present.

Subscript

A small number written below and to the right of an element symbol, indicating the number of atoms in a molecule.

Solid

A substance with a fixed shape and volume.

Liquid

A substance with a definite volume that takes the shape of its container.

Gas

A substance with no fixed shape or volume, expanding to fill its container.

Aqueous Solution

A substance dissolved in water, indicated by the symbol (aq).

Atom

The smallest unit of an element that retains its properties.

Element

A pure substance made of only one type of atom.

Combustion Reaction

A reaction where a substance reacts with oxygen, releasing energy as heat and light.

Decomposition Reaction

A reaction where a single compound breaks down into simpler substances.

Synthesis Reaction

A reaction where two or more substances combine to form a single product.

Single Replacement Reaction

A reaction where one element replaces another in a compound.

Double Replacement Reaction

A reaction where two compounds swap elements to form new compounds.

Counting Atoms in an Equation

Multiply the coefficient by the subscript for each element to count the number of atoms.

Arrow in Chemical Equations

The arrow (→) represents the reaction direction, meaning 'yields' or 'produces'.

Steps to Balancing an Equation

1. List all elements. 2. Count atoms on both sides. 3. Adjust coefficients to make atoms equal. 4. Check and simplify.