3.4 Atmosphere & acids Flashcards
(87 cards)
1
Q
What is pH < 7?
A
acidic
2
Q
What is acidic?
A
pH < 7
3
Q
What is pH = 7
A
neutral
4
Q
What is neutral?
A
pH = 7
5
Q
What is pH > 7?
A
alkaline
6
Q
What is alkaline?
A
pH > 7
7
Q
What is a strong acid?
A
0-3
8
Q
What is the colour of a strong acid on the universal indiator?
A
red
9
Q
What is a weak acid?
A
3-6
10
Q
What is the colour of a weak acid on the universal indictaor?
A
orange 3-4
yellow 5-6
11
Q
What is the colour of a neutral substance on the universal indicator?
A
green
12
Q
What is a weak alkali?
A
8-10
13
Q
What is the colour of a weak alkali on the universal indicator?
A
light blue
14
Q
What is a strong alkali?
A
11-14
15
Q
What is the colour of a strong alkali on the universal indicator?
A
dark blue 11-13
purple 14
16
Q
What is the colour of an acid in methyl orange?
A
red
17
Q
What is the colour of a neutral in methyl orange?
A
yellow
18
Q
What is the colour of an alkali in methyl orange?
A
yellow
19
Q
What is the colour of an acid in phenolphthalein?
A
colourless
20
Q
What is the colour of a neutral in phenolphthalein?
A
colourless
21
Q
What is the colour of an alkali in phenolphthalein?
A
pink
22
Q
What is the colour of an acid using red litmus paper?
A
red
23
Q
What is the colour of a neutral using red litmus paper?
A
red
24
Q
What is the colour of an alkali using red litmus paper?
A
blue
25
What is the colour of an acid using blue litmus paper?
red
26
What is the colour of a neutral using blue litmus paper?
blue
27
What is the colour of an alkali using blue litmus paper?
blue
28
What is the approx % of nitrogen in the air?
78%
29
What is the approx % of oxygen in the air?
21%
30
What is the approx % of argon in the air?
0.96%
31
What is the approx % of carbon dioxide in the air?
0.04%
32
What is the formula for working out the composition of air?
final - initial x 100
33
How do you measure the percentage of oxygen?
react oxygen with another element
often a metal
air will gradually decrease in volume until all oxygen has been reacted
34
What might go wrong when investigating the percentage of oxygen in the air?
wasn't done for long enough
leak in apparatus
- so not all oxygen was reacted
35
What is element combustion?
element + oxygen -> element oxide
36
What state is a metal oxide?
solid
37
What state is a non-metal oxide?
gas
38
What observations can be made when magnesium oxide forms?
bright white light
white powder
39
What observations can be made when sulphur dioxide forms?
blue flame
40
What observations can be made when water forms?
squeaky pop
41
What is the chemical test for oxygen?
glowing splint relights
42
What happens to water when a metal oxide dissolves in it?
becomes alkaline
pH 8-14
43
What happens to water when a non-metal oxide dissolves in it?
becomes acidic
pH 0-6
44
Define acid
H+ donor
45
Define base
H+ acceptor
46
Define alkali
OH- donor
47
What is the difference between acid and acidic?
acid ; describes a substance in terms of ions
acidic ; pH of solution
48
What is the difference between alkali and alkaline?
alkali ; describes a substance in terms of ions
alkaline ; pH of solution
49
What happens when an acid reacts with water?
acid dissolves
donates H+
makes pH 0-6
50
What happens when an alkali reacts with water?
alkali dissolves
donates OH-
makes pH 8-14
51
What happens when a base reacts with water?
base dissolves
accepts H+ from H2O
OH- ion formed
makes pH 8-14
52
What is the formula for hydrochloric acid?
HCl
53
What is HCl?
hydrochloric acid
54
What is the formula for nitric acid?
HNO3
55
What is HNO3?
nitric acid
56
What is the formula for sulphuric acid?
H2SO4
57
What is H2SO4?
sulphuric acid
58
What is the formula for phosphoric acid?
H3PO4
59
What is H3PO4?
phosphoric acid
60
What is the formula for carbonic acid?
H2CO3
61
What is H2CO3?
carbonic acid
62
What is the formula for sodium hydroxide?
NaOH
63
What is NaOH?
sodium hydroxide
64
What is the formula for potassium hydroxide?
KOH
65
What is KOH?
potassium hydroxide
66
What is the formula for ammonium hydroxide?
NH4OH
67
What is NH4OH?
ammonium hydroxide
68
What are soluble metal hydroxides?
alkalis
69
What is the formula for ammonia?
NH3
70
What is NH3?
ammonia
71
What are some important bases?
all metal oxides
all metal hydroxides
72
Define polyatomic ion
ion that contains more than one atom
released by acids
73
What is the polyatomic ion released by nitric acid?
nitrate
NO3
74
What is the polyatomic ion released by sulphuric acid?
sulphate
SO4
75
What is the polyatomic ion released by phosphoric acid?
phosphate
PO4
76
What is the polyatomic ion released by carbonic acid?
carbonate
CO3
77
What is the reaction called between an acid and a base?
neutralisation
78
What is neutralisation?
reaction between an acid and a base
79
What is the equation of neutralisation?
acid + base -> water + salt
80
What observations can be made during neutralisation?
base disappears
has been used up in reaction
81
Describe crystallisation (4)
1. add base to acid
2. filter excess base
3. heat salt solution until crystals form at edges
4. leave to crystallise
82
In crystallisation, why is excess base added?
ensure all acid is used up
83
In crystallisation, why is the acid heated?
speed up reaction
84
In crystallisation, why is the excess base filtered?
remove any solids before heating
85
In crystallisation, how does heating make the crystals form?
saturates the solution
86
What are the products in an acid + carbonate reaction?
salt, water and carbon dioxide
87
What observations can be made in an acid + carbonate reaction?
carbonate disappears and is used up
effervescence because CO2 is produced
