inorganic chemistry - acids, bases & salt preparations

Question 1

6 rules for predicting solubility

Answer 1

1. sodium, potassium and ammonium are ALL soluble
2. ALL nitrates are soluble
3. chlorides are soluble EXCEPT silver and lead chloride
4. sulfates are soluble EXCEPT barium, calcium and lead sulfate
5. carbonates are insoluble EXCEPT sodium, potassium and ammonium
6. hydroxides are insoluble EXCEPT sodium, potassium and calcium

Question 2

what is an acid in terms of protons?

Answer 2

a proton donor. It has a low pH

Question 3

what is a base in terms of protons?

Answer 3

a proton acceptor. it has a high pH

Question 4

what happens when alkali and acid react?

Answer 4

alkali + acid –> water + salt

Question 5

what happens when base and acid react?

Answer 5

base + acid –> water + salt

Question 6

what happens when carbonate and acid react?

Answer 6

carbonate + acid –> water + salt + carbon dioxide

Question 7

what happens when metal and acid react?

Answer 7

metal + acid –> salt + hydrogen

Question 8

mnemonic to remember the acid, alkali, carbonate and metal reactions

Answer 8

AAWS
BAWS
CAWS COD
MASH

Question 9

what happens to alkalis that are bases in water

Answer 9

they are soluble

Question 10

3 things that are usually bases

Answer 10

metal oxide, a metal hydroxide or ammonia.

Question 11

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

Answer 11

• Heat acid (H2SO4) in a beaker to speed up the rate of reaction
• Add base (CuO) until in excess (no more copper oxide dissolves) and stir with glass rod to neutralise all the acid
• Filter the mixture using filter paper and funnel to remove any excess copper oxide
• Gently heat the filtered solution (CuSO4) to evaporate some of the water
  until crystals form on a glass rod. this shows a hot saturated solution formed
• Allow the solution to cool so that hydrated crystals form Copper sulfate is less soluble in cold solution
• Remove the crystals by filtration
• Dry by leaving in a warm place. This evaporates the water