Chemical Changes

Question 1

What do acids form in water?

Answer 1

H+ ions

Question 2

What is a base?

Answer 2

A substance that reacts with an acid to produce a salt and water

Oxides and hydroxides

Question 3

What do alkalis form in water?

Answer 3

OH- ions

Question 4

What happens to the pH when the concentration of hydrogen ions increases?

Answer 4

The pH decreases

Question 5

What happens to the pH when the concentration of OH- ions increases

Answer 5

The pH increases

Question 6

What colour is litmus in:

Acid?

Neutral?

Alkali?

Answer 6

Acid: red

Neutral: purple

Alkali: blue

Question 7

What colour is methyl orange in:

Acid?

Neutral and alkali?

Answer 7

Acid: red

Neutral and alkali: yellow

Question 8

What colour is phenolphthalein in:

Acid and neutral?

Alkali?

Answer 8

Acid and neutral: colourless

Alkali: pink

Question 9

What is the concentration of an acid?

Answer 9

How watered down it is

Question 10

What happens to the pH if the concentration of H+ ions increases by a factor of 10?

Answer 10

It decreases by 1

Question 11

What is the gas test for chlorine?

Answer 11

Damp blue litmus paper turns red then bleaches white

Question 12

What is the what is the gas test for oxygen?

Answer 12

Glowing splint relights

Question 13

What is the gas text for carbon dioxide?

Answer 13

Limewater goes cloudy

Question 14

What is the gas test for hydrogen?

Answer 14

Lit splint in hydrogen makes squeaky pop

Question 15

How do you make a soluble salt?

Answer 15

Acid + insoluble base

Question 16

How do you make an insoluble salt?

Answer 16

Soluble salt + soluble salt

Question 17

What are the 5 steps of titration?

Answer 17

1. Measure out acid into conical flask and add indicator
2. Slowly add alkali using burette until the indicator changes colour
3. Redo the reaction without the indicator
4. The solution now only contains salt and water
5. Evaporate the water

Question 18

What is electrolysis?

Answer 18

The breaking down of a substance using electricity

Question 19

What is a positive ion called?

Answer 19

Cation

Question 20

What is a negative ion called?

Answer 20

Anion

Question 21

What is a positive electrode called?

Answer 21

Anode

Question 22

What is a negative electrode called?

Answer 22

Cathode

Question 23

What is electrolyte?

Answer 23

The liquid which carries the charges

Question 24

What current is used for electrolysis?

Answer 24

Direct current

Question 25

What does OILRIG stand for?

Answer 25

``` Oxidation Is Loss (of electrons) Reduction Is Gain (of electrons) ```

Question 26

What happens to anions at the anode?

Answer 26

They are oxidised

Question 27

Where are non metals discharged in electrolysis?

Answer 27

At the anode

Question 28

What happens to cations at the cathode?

Answer 28

They are reduced

Question 29

Where are metals discharged in electrolysis?

Answer 29

The cathode

Question 30

Why is electrolysis easier with a molten electrolyte?

Answer 30

Because there are no H+ or OH- ions

Question 31

Why is electrolysis harder with aqueous solutions?

Answer 31

Because it contains H2O/H+ and OH- ions

Question 32

Are 'all common sodium, potassium and ammonium salts' soluble or insoluble?

Answer 32

Soluble

Question 33

Is silver chloride soluble or insoluble?

Answer 33

Insoluble

Question 34

Are all nitrates soluble or insoluble?

Answer 34

Soluble

Question 35

Are Lead sulphate Barium sulphate Calcium sulphate Soluble or insoluble?

Answer 35

Insoluble

Question 36

Are most chlorides soluble or insoluble?

Answer 36

Soluble

Question 37

Are most carbonates soluble or insoluble?

Answer 37

Insoluble

Question 38

Are Sodium carbonate Potassium carbonate Ammonium carbonate Soluble or insoluble?

Answer 38

Soluble

Question 39

Are most hydroxides soluble or insoluble?

Answer 39

Insoluble

Question 40

Are Sodium hydroxide Potassium hydroxide Ammonium hydroxide Soluble or insoluble?

Answer 40

Soluble