P1: Chemical Changes

Question 1

The more reactive a metal is…

Answer 1

-The more vigorous its reactions are
-The more easily it loses electrons to form ions

Question 2

What are the products of reactions of metals with water?

Answer 2

A metal hydroxide and hydrogen.

Question 3

What is produced when a metal reacts with a dilute acid?

Answer 3

A salt and hydrogen

Question 4

What are the products of a reaction of metal with oxygen?

Answer 4

A metal oxide.

Question 5

What type of metal displaces another one in a displacement reaction?

Answer 5

A more reactive metal displaces a less reactive one,

Question 6

What is oxidation?

Answer 6

The gain of oxygen or loss of electrons

Question 7

What is reduction?

Answer 7

The loss of oxygen or gaining of electrons.

Question 8

What is ore?

Answer 8

A rock containing enough quantities of a mineral for extraction to be possible.

Question 9

What are the problems with extracting aluminium from its ore?

Answer 9

Aluminium has a high melting point, and aluminium oxide is insoluble in water.

Question 10

What is used instead of water to extract aluminium from aluminium oxide?

Answer 10

Cryolite.

Question 11

What are the electrodes in electrolysis made out of?

Answer 11

Graphite.

Question 12

What is the name of the positive electrode?

Answer 12

Anode

Question 13

What is the name of the negative electrode?

Answer 13

Cathode.

Question 14

What happens at the electrodes during the electrolysis of aluminium oxide?

Answer 14

-At the cathode, aluminium ions gain electrons and form atoms.
-At the anode, oxide ions lose electrons and form oxygen gas.

Question 15

What do acids produce in aqueous solution?

Answer 15

H+ ions

Question 16

What do alkalis produce in aqueous solution?

Answer 16

OH- ions

Question 17

What is the name of the scale that measures the acidity or alkalinity of a solution?

Answer 17

pH scale.

Question 18

What is a base?

Answer 18

Any substance that reacts with an acid to form a salt and water only. Metal oxides and metal hydroxides are bases.

Question 19

What is produced when a base reacts with an acid?

Answer 19

Salt and water.

Question 20

What is the other term for bases that are soluble in water?

Answer 20

Alkalis.

Question 21

What is a neutralisation reaction?

Answer 21

A reaction between an acid and a base.

Question 22

How do you make a salt in general?

Answer 22

React a metal oxide with an acid.

Question 23

What is produced when an acid reacts with a carbonate?

Answer 23

Salt, water and carbon dioxide.

Question 24

How do you make salt? Explain simply.

Answer 24

-Add powdered insoluble reactant to acid in beaker one spatula at a time. Continue adding powder until it is in excess.
-Filter the mixture in the beaker to remove the excess solid.
-Heat the solution in an evaporating dish over a water bath. Stop heating when small crystals start to appear around the edge of the evaporating basin.
-Leave the solution at room temp for a day.

Question 25

Give some examples of strong acids.

Answer 25

Nitric acid, sulfuric acid, Hydrochloric acid.

Question 26

Give an example of a weak acid.

Answer 26

Ethanoic acid.

Question 27

The higher the concentration of H+ ions in an acidic solution…

Answer 27

The lower the pH.

Question 28

What equipment is needed for a titration calculation?

Answer 28

-A pipette and filler -A burette -A conical flask -White tile

Question 29

What is the purpose of titrations?

Answer 29

-To determine the reacting volumes of solutions of an acid and alkali by titration. -To determine the concentration of one of the solutions.

Question 30

What are suitable indicators for titration calculations?

Answer 30

Phenolphthalein or methyl orange.

Question 31

What colour do phenolphthalein change to?

Answer 31

Pink in alkaline conditions, colourless in neutral.

Question 32

What is the colour change in methyl orange?

Answer 32

In alkali or basic, it is yellow. In acidic, it is red

Question 33

What are the reagents in a titration calculation?

Answer 33

-An acid of unknown concentration -Sodium Hydroxide solution of known concentration -A suitable indicator

Question 34

What is an electrolyte?

Answer 34

A substance which, when molten or in solution, will conduct an electric current

Question 35

Which electrode to H+ ions go to?

Answer 35

The cathode.

Question 36

Which electrode do OH-ions go to?

Answer 36

The anode.

Question 37

When is hydrogen produced at the cathode?

Answer 37

If the metal is more reactive than hydrogen.

Question 38

Which 3 metals are less reactive than hydrogen?

Answer 38

Copper, silver and gold.

Question 39

When do OH- ions NOT go to their electrode?

Answer 39

If Group 7 ions are present

Question 40

What is a half equation?

Answer 40

An equation that demonstrates how an atom has lost or gained electrons.

Question 41

Explain why the pH of an acid depends on the strength of the acid.

Answer 41

The stronger an acid the greater the ionisation, so the lower the pH.

Question 42

Explain why the pH of an acid depends on the concentration of the acid.

Answer 42

The higher the concentration of an acid the more acid in the same volume of solution So the higher the concentration of the acid the lower the pH

Question 43

Are alkaline batteries rechargable?

Answer 43

No.