Acids and bases

Learning goals We are learning to identify acids and bases. We are learning to use the pH scale to determine the strength of acids and bases.

Properties of acids An acid is a compound that: tastes sour corrodes metals and tissue conducts electricity when dissolved in water react with metals turns blue litmus paper red

Properties of bases An base is a compound that: tastes bitter has a slippery texture conducts electricity when dissolved in water corrodes tissue don‘t react with metals turns red litmus paper blue

Acid-base indicators a substance that changes colour when added to an acid or a base. Litmus paper is a type of acid-base indicator that often comes in two colours: red and blue. Acids turn blue litmus paper red. Bases turn red litmus paper blue.

pH scale The pH scale is a scale from 0 to 14 that describes how acidic or basic a substance is. The lower the pH number, the more acidic a substance is. The higher the pH number, the more basic a substance is.

When pH changes by one, the strength of the acid or base changes by ten times.

Naming acids Ionic compounds with a hydrogen as the metal attached to a non-metal use prefix “hydro” stem of element suffix “ic” word “acid” HCl: hydrochloric acid

Naming bases Usually have an –OH (hydroxide) group attached to a metal NaOH – sodium hydroxide

Learning goals We are learning to identify acids and bases. We are learning to use the pH scale to determine the strength of acids and bases.