Acids and Alkalis

What do all acids contain

Hydrogen, they will all produce H+ ions

What happens when an acid dissolves in water

It produces H+ ions (protons)

What does a base do to an acid

Neutralises it

What is different from an alkali and a base

An alkali is a base dissolved in water that will produce OH- ions

Acid + metal → …

Salt + hydrogen

Acid + metal carbonate → …

Salt + carbon dioxide + water

Acid + base → …

Salt + water

Acid + alkali → …

Salt + water

What type of salt will form when HCL is neutralised by an alkali

Chloride

What type of salt will form when nitric acid is neutralised by an alkali

Nitrate

What type of salt will form when sulphuric acid is neutralised by an alkali

Sulphate

What is the difference between a strong acid and a weak acid

A strong acid is completely ionised in solution

A weak acid is incompletely ionised in solution

How does strength of acid affect on reactivity

Strong acids are more reactive ad they have a higher concentration of H+ ions

Vice versa

How does strength of acid affect pH

The pH of a strong acid will be lower than the pH of a weak acid in the same concentration because the concentration of H+ ions is greater

How does acid concentration affect pH

Thr pH will decrease with increasing acid concentration regardless of the acids strength

What’s the difference between acid strength and acid concentration

Acid strength is what proportion of the acid molecules ionised in water. Concentration measures the total number of dissolved acid molecules there are in a certain volume of water

How is a salt formed

When the H+ ions in an acid is replaced with a metal ion

What 3 types of salt are ALWAYS soluble

Nitrates, group 1 salts, and ammonium salts

What types of salt are mostly soluble with some exceptions. What are the exceptions

Group 7 salts, sulphate salts

Exceptions - silver, lead, barium, mercury

What salts are insoluble ( take into account exceptions based on salts that are always soluble )

Carbonates, hydroxide, phosphates

What is reduction

When a species gains electrons

What is oxidation

When a species loses electrons

What is a formulation

A useful mixture with a specific purpose made by following a formula with specific proportions of each substance

What do fertilisers often contain

Phosphorous, potassium, and nitrogen

How are these chemicals sourced for use in fertiliser

KCL, K2SO4 and phosphate rock are all mined

Phosphate rock + nitric acid → ….

Phosphoric acid + calcium nitrate

Phosphate rock + phosphoric acid → …

Calcium phosphate (triple super phosphate)

Phosphate rock + sulphuric acid → …

Calcium phosphate + calcium sulphate

What is a disadvantage of using fertilisers

If too much fertiliser is used it will cause eutrophication

How do you produce a soluble salt from sulphuric acid and copper oxide

Gently heat a beaker of acid and repeatedly add spatulas of the copper oxide until not more will dissolve. The acid has been neutralised. Then use filter paper to filter away the excess copper oxide and leave the salt solution. Then add the solution to an evaporating basin. Heat the solution to evaporate some of the liquid and make the concentration higher. then leave the basin on the windowsill and crystals should form around the edges. Then filter and dry the crystals

CuO + H2SO4 → …

CuSO4 + H20

How can you work out which method to use to produce a salt

Is the salt soluble?

No: precipitate method then filter and dry

Yes: is the salt in group 1?

No: react acid with the metal/ metal oxide/metal carbonate/ hydroxide in excess. Then filter and put in evaporating basin

Yes : titration method