Preparation and Tests

Question 0

Test for ammonia

Answer 0

Damp litmus paper blue

Damp universal indicator purple

Question 1

Calculating electrolysis product amounts

Answer 1

Write out half equation
Calculate coulombs from current
Calculate electron moles (coulombs/faradays)
Scale factor electron moles to get product moles
Calculate mass

Question 2

Test for chlorine

Answer 2

Bleaches damp litmus paper white

Question 3

Test for sulphate ions

Answer 3

(Sulphate)+ HCl + Barium Chloride -> barium sulphate precipitate ( white)

Question 4

Tests for chlorine, bromine and iodine

Answer 4

Test with nitric acid and silver nitrate
Chlorine - White precipitate
Bromine - cream precipitate
Iodine - yellow precipitate

Question 5

Flame test - Lithium ions

Answer 5

Red flame

Question 6

Flame test - sodium ions

Answer 6

Orange flame

Question 7

Flame test -potassium ions

Answer 7

Lilac flame

Question 8

Flame test - Calcium ions

Answer 8

Brick red flame

Question 9

Test for positive ions

Answer 9

Metal salt + sodium hydroxide = precipitate in a few cases i.e insoluble metals

Question 10

Sodium hydroxide + copper ions =

Answer 10

Blue precipitate of copper hydroxide

Question 11

Sodium Hydroxide + Iron 3 ions =

Answer 11

Orange brown precipitate

Question 12

Sodium hydroxide + iron 2 ions =

Answer 12

Green precipitate

Question 13

Sodium hydroxide + ammonium salt =

Answer 13

No precipitate but smell of ammonia

Question 14

Test for carbonates

Answer 14

Add acid ( preferably nitric) and look for carbon dioxide bubbles

Question 15

Solubility Rules

Answer 15

All sodium, potassium and ammonium compounds are soluble
All carbonates and hydroxides are insoluble apart from above
All chlorides are soluble except lead chloride and silver chloride
All sulphates are soluble except Barium Sulphate, lead sulphate and Calcium sulphate

Question 16

Salt preparation

Answer 16

React the alkaline metal with the acid to form a salt mixture - In the cold if carbonate or magnesium, otherwise by heating
Use an excess of the alkali to maximise output
Filter off excess alkali and heat concentrated salt solution .
Test by dipping a glass rod in to see if crystals form.
Alternatively do a titration.

Question 17

Rules for making salts

Answer 17

If not soluble, use precipitation method
If soluble but not sodium, potassium or ammonium, react with an excess of metal
If soluble and one of three above, use a titration method