Atmosphere and acids

Question 1

What is an indicator?

Answer 1

a substance that changes colour in acid, alkali, neutral

Question 2

What colour is an acid in methyl orange?

Answer 2

red

Question 3

What colour is an acid in phenolphthalein?

Answer 3

colourless

Question 4

What colour is an acid in universal indicator?

Answer 4

red

Question 5

What colour is an acid in blue litmas?

Answer 5

red

Question 6

What colour is an acid in red litmus?

Answer 6

red

Question 7

What colour is neutral in methyl orange?

Answer 7

yellow

Question 8

What colour is neutral in phenolphthalein?

Answer 8

colourless

Question 9

What colour is neutral in universal indicator?

Answer 9

green

Question 10

What colour is neutral in blue litmas?

Answer 10

blue

Question 11

What colour is neutral in red litmas?

Answer 11

red

Question 12

What colour is alkali in methyl orange?

Answer 12

orange/yellow

Question 13

What colour is alkali in phenolphthalein?

Answer 13

pink

Question 14

What colour is alkali in universal indicator?

Answer 14

dark blue

Question 15

What colour is alkali in blue litmas?

Answer 15

blue

Question 16

What colour is alkali in red litmas?

Answer 16

blue

Question 17

Universal indicator:
acid?

Answer 17

1-6
strong acid = 1-3

Question 18

Universal indicator:
neutral?

Answer 18

7

Question 19

Universal indicator:
alkaline?

Answer 19

8-16
strong alkaline = 12-16

Question 20

Examples of weak acid, strong acid, neutral, weak alkaline, strong alkali?

Answer 20

strong acid = sulphuric, batteries
weak acid = fruit
neutral = water, blood
weak alkaline = soap
strong alkaline = bleach

Question 21

What is the composition of air, no water vapour?

Answer 21

nitrogen = 78%
oxygen = 21%
argon = 0.9%
carbon dioxide = 0.04%
other gases = trace amounts

Question 22

Copper + oxygen = copper oxide
what happens in syringe?

Answer 22

heat (brown) copper
(black) copper oxide formed (greater mass than copper)
volume of air decreases as oxygen is used up

Question 23

Copper + oxygen = copper oxide
Why does the pile of copper oxide turn black?

Answer 23

has been oxidised
reacted with oxygen and produced copper (II) oxide

Question 24

Copper + oxygen = copper oxide
Why should syringe be cooled before measuring volume?

Answer 24

gases expand when heated therefore letting it cool = more accurate result

Question 25

Copper + oxygen = copper oxide Why might we not get 21%

Answer 25

not all oxygen reacts (less than 21%) leak in equipment lets in more air

Question 26

What is the fire triangle?

Answer 26

fuel + oxygen + heat

Question 27

What is combustion?

Answer 27

when a substance reacts with oxygen

Question 28

Substance + oxygen -> ?

Answer 28

oxides

Question 29

Element + oxygen -> ?

Answer 29

dioxides

Question 30

metals + oxygen -> ?

Answer 30

metal oxide

Question 31

non-metal + oxygen -> ?

Answer 31

non-metal dioxide

Question 32

metal oxide + water = ?

Answer 32

alkaline solution

Question 33

non-metal dioxide + water = ?

Answer 33

acidic solution

Question 34

How does magnesium react with pure oxygen?

Answer 34

bright white light cloudy solution UI = green/blue, alkaline

Question 35

How does carbon react with pure oxygen?

Answer 35

orange flame UI = yellow, acidic

Question 36

How does iron react with pure oxygen?

Answer 36

orange glow UI = green insoluble

Question 37

How does sulphur react with pure oxygen?

Answer 37

blue flame UI = red, very acidic

Question 38

Why do materials burn better in oxygen than air?

Answer 38

More oxygen available in pure oxygen Greater chance of reaction happening

Question 39

Definition of acid?

Answer 39

H⁺ donor

Question 40

Definition of base?

Answer 40

H⁺ acceptor

Question 41

Definition of alkali?

Answer 41

OH⁻ donor (soluble hydroxides) Give up OH⁻ when dissolved in water

Question 42

What are bases?

Answer 42

Metal oxides Ammonium oxides Metal hydroxides Ammonium hydroxides Ammonia (as a gas) Metal carbonate

Question 43

What are alkalis?

Answer 43

NaOH (sodium hydroxide) KOH (potassium hydroxide) NH₄OH (ammonium hydroxide)

Question 44

Hydrochloric acid formula?

Answer 44

HCl

Question 45

Nitric acid formula?

Answer 45

HNO₃

Question 46

Sulphuric acid formula?

Answer 46

H₂SO₄

Question 47

Phosphoric acid formula?

Answer 47

H₃PO₄

Question 48

sulphuric acid + sodium hydroxide -> ?

Answer 48

sodium sulphate

Question 49

nitric acid + potassium hydroxide -> ?

Answer 49

potassium nitrate

Question 50

citric acid + copper oxide -> ?

Answer 50

copper citrate

Question 51

Order Mg Zn Cu and Pb in order of reactivity

Answer 51

Mg Zn/Pb Cu

Question 52

Metal + acid -> ?

Answer 52

hydrogen + salt metal gets smaller/ disappear squeaky pop/ effervescence

Question 53

Magnesium + sulphuric acid -> ?

Answer 53

hydrogen + magnesium sulphate Mg displaces H₂

Question 54

Copper + sulphuric acid -> ?

Answer 54

no reaction Cu is less reactive than H₂ so can't displace

Question 55

What are the solubility rules?

Answer 55

Soluble: All group 1, ammonium salts and nitrates Most halides except: silver and lead most sulphates except: lead, barium, calcium Insoluble: Oxides, hydroxides, carbonates except: group 1 and ammonium

Question 56

acid + base -> ?

Answer 56

salt + water if solid, salt will disappear water shows neutralisation

Question 57

How do you make crystals from an acid and base?

Answer 57

Heat acid (to speed up reaction) Add excess base (all of acid reacts) Filter out excess base Heat until crystals just start to form Leave to crystallise

Question 58

acid + metal carbonate -> ?

Answer 58

salt + water + carbon dioxide metal carbonate disappears as it reacts CO₂ = effervescence

Question 59

test for water?

Answer 59

anhydrous copper sulphate turns from white to blue

Question 60

acid + alkali -> ?

Answer 60

salt + water

Question 61

ammonia in solution =

Answer 61

alkali