chemical changes

Question 1

What is produced when an acid and metal react?

Answer 1

Salt and hydrogen.

Question 2

What is a redox reaction?

Answer 2

When one substance is reduced and another substance is oxidised.

Question 3

Which 2 non metals are often included in the reactivity series?

Answer 3

Carbon and hydrogen.

Question 4

What colour flame does potassium produce?

Answer 4

Lilac

Question 5

What colour flame does sodium produce?

Answer 5

Yellow.

Question 6

What colour flame does lithium produce?

Answer 6

Red.

Question 7

What colour flame does calcium produce?

Answer 7

Orange/Red.

Question 8

What is displacement?

Answer 8

When a more reactive element displaces a less reactive element from a compound.

Question 9

What is oxidation?

Answer 9

When oxygen gains electrons and fills its outer shell from another element that loses its outer shell and electrons.

Question 10

What is reduction?

Answer 10

Gaining electrons but losing oxygen or gaining hydrogen.

Question 11

What do an acid + a base produce?

Answer 11

Salt + water

Question 12

Acids are neutralised by metal carbonates to produce…

Answer 12

Salt, water and carbon dioxide.

Question 13

What salts does hydrochloric acid produce?

Answer 13

Chlorides.

Question 14

What salts does nitric acid produce?

Answer 14

Nitrates.

Question 15

What salts does sulfuric acid produce?

Answer 15

Sulfates.

Question 16

What do acids produce in aqueous solutions?

Answer 16

H+ ions.

Question 17

What do alkalis produce in aqueous solutions?

Answer 17

OH- ions.

Question 18

What happens to a strong acid in an aqueous solution?

Answer 18

It is completely ionised.

Question 19

What happens to a weak acid in an aqueous solution?

Answer 19

It is partially ionised.

Question 20

Which elements in the reactivity series react with water?

Answer 20

Potassium, sodium, lithium and calcium.

Question 21

What elements in the reactivity series react with dilute acid?

Answer 21

Calcium, magnesium, zinc, iron and copper.

Question 22

Gold is very unreactive since…

Answer 22

It is found in the earth as the metal itself.

Question 23

What do metal compounds require to extract the metal?

Answer 23

Chemical reactions.

Question 24

Metals less reactive than carbon can be extracted from their oxides by…

Answer 24

Reduction with carbon.

Question 25

What are soluble salts made from?

Answer 25

Acids by reacting them with solid insoluble substances.

Question 26

What do you fill the burette with in the titration practical?

Answer 26

100cm cubed of acid.

Question 27

What do you use a pipette for during the titration practical?

Answer 27

To add 25cm cubes of alkali to the conical flask.

Question 28

What is a titre?

Answer 28

The volume of acid needed to exactly neutralise.

Question 29

What are the 4 steps for working out concentration?

Answer 29

1. Convert volumes into dm cubed
2. Work out moles
3. Work out the molar ratio
4. Work out the concentration

Question 30

When an ionic substance is melted or dissolved, ions are…

Answer 30

Free to move.

Question 31

Passing a current through substances that are a solution or molten means…

Answer 31

The substance can be broken down into elements. (electrolysis)

Question 32

What is the name for the substance being broken down in electrolysis?

Answer 32

The electrolyte.

Question 33

What is produced when ions are discharged at the electrodes?

Answer 33

Elements.

Question 34

In electrolysis, positively charged ions move to…

Answer 34

The negative electrode (cathode).

Question 35

In electrolysis, negatively charged ions move to…

Answer 35

The positive electrode (anode).

Question 36

What is the ionic equation at the negative electrode?

Answer 36

X+ + e- —> X and electrons are gained so positive ions are reduced.

Question 37

What is the ionic equation at the positive electrode?

Answer 37

X- —> e- + X and electrons are lost so negative ions are oxidised.