Acids, bases & salts

Question 1

describe the use of litmus, phenolphthalein and methyl orange to distinguish between acidic and alkaline solutions

Answer 1

Question 2

understand how to use the pH scale, from 0–14

Answer 2

Question 3

describe the use of Universal Indicator

Answer 3

Question 4

acid (in aqueous solution) definition

Answer 4

source of hydrogen ions (H+)

Question 5

alkali (in aqueous solution) definition

Answer 5

source of hydroxide ions (OH–).

Question 6

describe a neutralisation reaction

Answer 6

Metal oxides, metal hydroxides and ammonia (NH₃) are called bases.

Bases neutralise acids by combining with the hydrogen ions in them.

The key reaction is:
acid + base → salt + water

An example of this is:
sulfuric acid + copper oxide → copper sulfate + water

(H₂SO₄ + CuO → CuSO₄ + H₂O)

Question 7

acid + alkali

Question 8

acid + base

Question 9

acid + carbonate

Question 10

acid + metal

Question 11

know the general rules for predicting the solubility of ionic compounds in water

Answer 11

SPA (sodium, potassium, ammonium) = SOLUBLE

Nitrates = soluble

chlorides = soluble (except silver & lead)

sulfates = soluble (except barium, calcium lead)

hydroxides = insoluble (except SPA + calcium)

carbonates = insolulbe (except SPA)

Question 12

describe an experiment to prepare a pure, dry sample of a soluble salt, starting from an insoluble reactant

Answer 12