Acids, Bases And Salts

Question 1

What is an acid?

Answer 1

A proton (H+) donor that release H+ in aqueous solutions.

Question 2

Examples of 3 strong acids:

Answer 2

HCl
H2SO4
HNO3

Question 3

What do strong acids do in solution?

Answer 3

They completely dissociate and release all their H+ ions

Question 4

What is an example of a weak acid?

Answer 4

CH3COOH ethanoic acid

Question 5

What do weak acids do in solution?

Answer 5

Partially dissociate as they don’t release all their H+ ions

Question 6

What is a base?

Answer 6

A proton (H+) acceptor

Question 7

What is an alkali?

Answer 7

A base dissolved in water that release OH- in aqueous solution

Question 8

What are some examples of important bases?

Answer 8

Hydroxide
Oxides
Carbonates
Ammonia

Question 9

Give some examples of strong alkalis and what do they do in solution?

Answer 9

NaOH KOH

They completely dissociate into separate ions

Question 10

Why is ammonia a weak alkali?

Answer 10

In aqueous solution only some NH3 molecules react with water to produce a low concentration of OH-(aq)
Only partial dissociation

Question 11

What is a salt and give some examples:

Answer 11

Produced whenever the H+ of an acid is replaced by a metal ion or NH4+

E.g chloride, nitrate, sulfate salts

Question 12

What are the 4 neutralisation reaction equations to make a salt?

Answer 12

1. Acid+ alkali -> salt + water
2. Acid+ metal oxide -> salt + water
3. Acid + carbonate -> salt+ carbon dioxide + water
4. Acid + ammonia-> ammonium salt

Question 13

What is the fifth way a salt can be made?

Answer 13

Acid + metal -> salt and hydrogen

Question 14

What does an ionic equation show?

Answer 14

Shows the ions in a reaction that are CHANGED - even if it’s just there state

Question 15

What happens in precipitation reactions of salt solutions?

Answer 15

A solid ionic compound forms when 2 ionic solutions are mixed

Question 16

What is water of crystallisation?

Answer 16

The fixed number of water molecules within a hydrated crystal compound structure
(Represented by a dot followed by the fixed number)

Question 17

What is a crystal?

Answer 17

A solid containing particles arranged in a regular way

Question 18

What does a hydrated compound?

Answer 18

A crystalline compound that contains water molecules

Question 19

What does an anhydrous compound mean?

Answer 19

A crystal compound contains no water molecules

Question 20

What colour in copper(II) sulfate when hydrated and anhydrous?

Answer 20

Hydrated- blue crystals

Anhydrous- White crystals

Question 21

How do you work out the water of crystallisation?

Answer 21

1. Find mass of water
= mass of hydrated- mass of anhydrous 
2. Find mole of water
n=m/M
3. Work out mole of salt (anhydrous) 
n=m/M
4. Calculate the no of water present for 1 mole of salt with a ratio of the moles

Question 22

When we heat the hydrated salt what must we make sure we do?

Answer 22

Re-heat until the mass no longer changes (to make sure all the water has evaporated)

Question 23

Why might a water of crystallisation experiment not be accurate?

Answer 23

Some anhydrous salts decompose on strong heating