chemistry specification part 5

Question 1

How do you prepare INSOLUBLE SALT by precipitation?

Answer 1

-place one soluble salt solution in a beaker
-add the other soluble salt solution until dissolved and stir to mix until no more precipitate forms.
-Filter out the precipitate using filter paper and a funnel inside a conical flask
-The residue is the insoluble salt you are trying to get.
-Wash the residue with water and let it dry in the oven

Question 2

what do the salts need to be before a precipitation experiment is carried out?

Answer 2

both soluble

Question 3

what do a base and an acid make?

Answer 3

salt and water

Question 4

Explain why, if soluble salts are prepared from an acid and an insoluble reactant that excess of the reactant is added?

Answer 4

there should be more base so that there is not any leftover acid in your product. The base will be in excess when all the acid has been neutralised and just excess solids sink to the bottom.

Question 5

what colours does litmus paper have?

Answer 5

red-acidic
purple-neutral
blue-alkaline

Question 6

what colours does methyl orange have?

Answer 6

red-acidic
yellow-neutral and alkaline

Question 7

what colours does phenolphthalein have?

Answer 7

colourless in acidic or neutral
pink in alkaline

Question 8

Explain what the products are if soluble salts are prepared from an acid and an
insoluble reactant

Answer 8

salt and water only

Question 9

Explain why, if soluble salts are prepared from an acid and an insoluble reactant, that excess reactant is removed

Answer 9

filtering off excess solids to get a solution containing only salt and water

Question 10

how to make soluble salts using an acid and an insoluble base

Answer 10

-heat the acid in a water bath
-then add the base to the acid and they will create to make soluble salt and water
-filter excess solids and heat solution gently using a bunsen burner and an evaporating dish to evaporate water so the salt can form crystals
-filter solid salt and let it dry