spec Flashcards
1
Q
whats the difference between a pure substance and a mixture?
A
- a pure substance has a fixed melting and boiling point
- a mixture may melt or boil over a range of temperatures
2
Q
do groups do down or sideways?
A
down,
there are 18 groups
3
Q
do periods do down or sideways
A
sideways, there are 7 periods
4
Q
how to calculate relative atomic mass (Ar)
A
sum of (ISOTOPE ABUNDANCE x ISOTOPE MASS)
___________________________________________
sum of ABUNDANCE OF ALL ISOTOPES
5
Q
how to calculate relative molecular mass (Mr)
A
the sum of all the individual atomic masses of all the atoms
6
Q
hydrogen ion
A
H (+)
7
Q
hydroxide ion
A
OH (-)
8
Q
ammonium ion
A
NH4 (+)
8
Q
carbonate ion
A
CO3 (2-)
9
Q
nitrate ion
A
NO3 (-)
10
Q
sulphate ion
A
SO4 (2-)
11
Q
how do the halogens change as you go down the group?
A
Halogens become less reactive and more solider in state
12
Q
colour and state of flourine at room temp
A
faintly yellow gas
13
Q
colour and state of chlorine at room temp
A
green gas
14
Q
colour and state of bromine at room temp
A
red-brown liquid
15
Q
colour and state of iodine at room temp
A
grey solid
16
Q
percentage of nitrogen in the air
A
78%
17
Q
percentage of oxygen in the air
A
21%
18
Q
percentage of argon in the air
A
almost 1%
19
Q
percentage of carbon dioxide in the air
A
0.04%
20
Q
what colour flame does magnesium produce when burned in oxygen?
A
a bright white flame
21
Q
what is the product of burning magnesium in oxygen?
A
magnesium oxide
22
Q
is magnesium oxide acid or alkaline when dissolved in water?
A
alkaline
23
Q
what colour flame does hydrogen produce when burned in oxygen?
A
a pale blue flame
24
what is the product of burning hydrogen in oxygen?
water vapour
25
is water vapour acid or alkaline?
neutral ph
26
what colour flame does sulphur produce when burned in oxygen?
a pale blue flame
27
what is the product of burning sulphur in oxygen?
sulphur dioxide
28
is sulphur dioxide acid or alkaline when dissolved in water?
acidic
29
what happens when you heat a metal carbonate?
thermal decomposition : it will break apart into a metal oxide and carbon dioxide
Metal carbonate ➔ metal oxide + carbon dioxide
30
What is the colour change when copper(II) carbonate decomposes to copper(II) oxide?
Green ➔ black
31
what two things react to form rust on iron?
oxygen and water
32
when alluminium corrodes what does it do that is different to when iron rusts?
it forms a protective layer meaning that only the surface atoms are affected by corrosion
33
barrier methods
- painting
- oil or grease
- electroplating (cover the iron in a thin layer of another metal)
34
sacrificial method
adding a more reactive metal to the iron so it gets oxidised first and the iron does not rust (e.g. "galvanising" - coating the object in a layer of zinc [can also be an example of a barrier method] )
35
test for chlorine gas
damp blue litmus paper bleaches (may turn red before bleaching)
36
safety precautions when testing for chlorine
chorine is poisonous so:
- wear a mask
- do it in a fume cupboard
37
test for ammonia gas
damp red litmus paper turns blue
38
why would scientist chose to use a polystyrene cup in a neutralisation reaction?
polystyrene is an insulator and so will reduce heat loss
39
how to calculate the amount of energy produced per gram in a combustion reaction
amount of energy produced
_____________________________
mass of --- burned
40
hydrochloric acid + sodium hydroxide
salt + water (neutralisation) :
sodium chloride + water
41
hydrogen ion + hydroxide ion
water
42
hydrochloric acid formula
HCl
43
sulfuric acid formula
H2SO4
44
nitric acid formula
HNO3
45
sodium hydroxide formula
NaOH
46
calcuim carbonate formula
CaCO3
47
what happens when Acids dissolve in Water to form an Aqueous Solution
they produce Hydrogen ions (H+) which makes the Aqueous Solution Acidic
48
what happens when Alkalis dissolve in Water to form an Aqueous Solution
they produce Hydroxide ions ( OH- ) which makes the Aqueous Solution an Alkali
49
test for carbonate ions
METHOD:
- Add Dilute Hydrochloric acid
- Gas produced is bubbled into limewater
- Colour of precipitate is observed and recorded
RESULT:
If Carbonate ions are present, limewater will turn milky
50
test for water
METHOD:
- Add liquid to Anhydrous Copper (II) Sulfate
- Colour change is observed and recorded
RESULT:
If liquid is water, white powder will turn Blue as Hydrated Copper (II) Sulfate is formed, which is a blue crystal
51
general formula for alkAnes
CnH2n + 2
52
methane
CH4
53
ethane
C2H6
54
propane
C3H8
55
butane
C4H10
56
order of hydrocarbons from lowest boiling point to highest boiling point
refinery gases, gasoline, kerosene, diesel, fuel oil, bitumen
57
order of hydrocarbons from least flammable to most flammable
bitumen, fuel oil, diesel, kerosene, gasoline, refinery gases
58
order of hydrocarbons from shortest chain length to longest chain length
refinery gases, gasoline, kerosene, diesel, fuel oil, bitumen
59
order of hydrocarbons from the lightest to the darkest
refinery gases, gasoline, kerosene, diesel, fuel oil, bitumen
60
what energy is released when a fuel is burned
heat energy
61
During the complete combustion of Hydrocarbons...
Carbon Dioxide and Water will be produced:
- Carbon will oxidise to form Carbon Dioxide
- Hydrogen will oxidise to Water
62
During the incomplete combustion of Hydrocarbons...
Carbon Monoxide and Water will be produced
63
why is incomplete combustion of hydrocarbons dangerous?
it releases Carbon Monoxide which is a poisonous Gas that reduces the capacity of red blood cells (haemoglobin) to carry Oxygen
64
what happens when the temperature in car engines is really high?
Nitrogen and Oxygen from the Air to combine to produce Nitrogen Monoxide:
Nitrogen + Oxygen → Nitrogen Monoxide
65
what happens when carbon monoxide is released from the exhaust of car engines
it combines with Oxygen in the Air to form Nitrogen Dioxide:
Carbon Monoxide + Oxygen → Nitrogen Dioxide
66
During combustion of Hydrocarbon fuels, impurities including Sulfur compounds will be oxidised to produce
Sulfur Dioxide:
Sulfur + Oxygen → Sulfur Dioxide
67
what causes acid rain?
Sulfur Dioxide released into the atmosphere will dissolve in Water droplets of clouds to make it more acidic (lower ph), resulting in Acid Rain
68
2 effects of acid rain
- Kills aquatic organisms - Rivers and lakes become too acidic which causes aquatic organisms to die
- Destroys buildings- Corrodes metals and limestone in buildings
69
Explain Why Alkanes are Classified as Saturated Hydrocarbons
all the bonds in an Alkane compound are single bonds
70
know that alkenes contain the functional group >C=C<
Alkenes contain double Carbon bond (shown as two lines between two Carbon atoms), allowing them to react in ways Alkanes cannot (more reactive)
71
general formula for alkEnes
CnH2n
72
why are alkenes classified as unsaturated hydrocarbons
they contain a double covalent bond
73
problems in the disposal of addition polymers
- Polymers are inert (unreactive) as they have strong C-C bonds.
This makes them non-biodegradeable.
- if burnt the addition polymers could produce toxic gases such as carbon monoxide
