Chemical Equations, Acids, and Bases 1

Chemical reaction

The chemical bonds in the reactants (starting materials) rearrange to form products (new chemical substances). The reactants “turn into” the products.

Reactants

Starting materials, found on the left of the reaction arrow (→).

Products

What is formed in a reaction, found on the right of the reaction arrow (→).

Conservation of mass

Total mass of the reactants = the total mass of the products. This also means that the number of each type of atom is the same from reactants to products. Atoms are simply rearranged into new substances, not created or destroyed.

Balance N₂ + H₂ → NH₃

N₂ + 3 H₂ → 2 NH₃

Balance H₂SO₄ + NaOH → Na₂SO₄ + H₂O

H₂SO₄ + 2 NaOH → Na₂SO₄ + 2 H₂O

Acids

Dissolve in water to produce H⁺. May taste sour. Solutions have pH < 7.

HCl, H₂SO₄, HNO₃, CH₃COOH

Examples of acids. (Hydrochloric acid, sulfuric acid, nitric acid, acetic acid)

Bases

React with acids via neutralization reactions. May taste bitter. Solutions have pH > 7.

NaOH, Mg(OH)₂, CuO

Examples of bases. (Sodium hydroxide, magnesium hydroxide, copper(II) oxide)

Alkalis

Bases that are soluble in water. Their solutions contain OH^- and have pH > 7.

Neutralization

Reaction between acid and base (to form salt and water).

Salt

Ionic compound which can be formed by reaction between acid and base.

Acid + Base →

Salt + Water (H₂O)

Acid + Metal →

Salt + Hydrogen (H₂)

Acid + Carbonate →

Salt + Carbon dioxide (CO₂) + Water (H₂O)

HCl + NaOH →

NaCl + H₂O (Acid-base reaction)

H₂SO₄ + Mg →

MgSO₄ + H₂ (Acid-metal reaction)

H₂SO₄ + CaCO₃ →

CaSO₄ + CO₂ + H₂O (Acid-carbonate reaction)