chemistry revision

Atoms

The basic units of matter that retain the properties of an element.

Acids

Substances in a chemical reaction that have a pH of less than 7.

Bases

Substances that have a pH of greater than 7, often used to neutralize acids.

pH of acids

Less than 7.

pH of bases

Greater than 7.

Hydrochloric acid (HCl)

An example of an acid.

Sulfuric acid (H₂SO₄)

An example of an acid.

Acetic acid (CH₃COOH)

An example of an acid.

Nitric acid (HNO₃)

An example of an acid.

Citric acid (C₆H₈O₇)

An example of an acid.

Sodium hydroxide (NaOH)

An example of a base.

Potassium hydroxide (KOH)

An example of a base.

Calcium carbonate (CaCO₃)

An example of a base.

Baking soda

An example of a base.

Universal indicator

An indicator of pH levels that changes color to determine pH, valuable in chemical experiments.

Phenolphthalein

A pH indicator that is colorless in acidic solutions and turns pink in alkaline solutions.

Litmus

A substance that turns red to indicate an acid and blue to indicate a base.

Methyl orange

A pH indicator that turns red in acidic solutions and yellow when neutral or alkaline.

acid + metal Reaction

Acid + metal → salt + hydrogen.

Hydrogen gas collection method

Place diluted hydrochloric acid in a test tube, add magnesium, and bring a glowing splint to produce a 'pop' sound.

Neutralization reaction

Acid + base → salt + water.

Example of neutralization reaction

Hydrochloric acid reacts with sodium hydroxide.

Preparation of Nickel Sulphate Crystals

Add nickel (II) carbonate to dilute sulphuric acid, filter excess, and heat to form crystals.