Chemistry Acids And Salts Topic- Key Knowledge

Question 1

What is an acid?

Answer 1

A proton donor

Question 2

What is an alkali?

Answer 2

A solution which neutralizes an acid

Question 3

What is a base?

Answer 3

A proton acceptor

Question 4

What color is litmus in an acid?

Answer 4

Red

Question 5

What color is litmus in an alkali?

Answer 5

Blue

Question 6

What color is Phenolphthalein in an acid?

Answer 6

Colourless

Question 7

What color is Phenolphthalein in an alkali?

Answer 7

Pink

Question 8

What color is Methyl orange in an acid?

Answer 8

Red

Question 9

What color is Methyl orange in an alkali?

Answer 9

Yellow

Question 10

Acids in aqueous solution are a source of what ions?

Answer 10

Hydrogen (H+)

Question 11

Alkalis in aqueous solution are a source of what ions?

Answer 11

Hydroxide (OH-)

Question 12

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

Answer 12

-Heat the acid gently
-Add the solid and stir
-Keep adding solid until no more dissolves
-Filter the mixture to remove excess solid
-Heat the filtrate until concentrated
-Leave the solution in an evaporating basin to cool and crystallise
-Decant crystals and pat them dry with a paper towel

Question 13

Describe an experiment to prepare a pure, dry sample of an insoluble salt, starting from two soluble reactants

Answer 13

-Measure both solutions separately
-Pour both into a beaker
-Filter the mixture to remove the spectator ions
-Wash the residue to further remove any soluble ions
-Remove the filter paper, open it out and leave to dry