Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Chemistry > paper 2 mock > Flashcards

paper 2 mock Flashcards

You may prefer our related Brainscape-certified flashcards:
Periodic Table flashcards Chemistry 101 flashcards AP® Chemistry flashcards Organic Chemistry 101 flashcards
1
Q

what is the current gas composition of the atmosphere

A 
nitrogen - 78%
oxygen 21%
carbon dioxide 0.04%
argon 0.9%
other less than 1%
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

the early gas composition of the atmosphere

A

lots of carbon dioxide
little to no oxygen
some water vapour
not much nitrogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

why did the atmosphere change

A

the earth’s surface cooled and a thin crust formed but volcanoes kept erupting releasing gases from inside the earth. This degassing released mainly carbon dioxide but also steam, methane and ammonia
when things settled down the atmosphere was mainly CO2 and water vapour and little oxygen. the water vapour condensed to form the oceans which absorbed the CO2

Nitrogen gas was then put into the atmosphere by ammonia reacting with nitrogen and by denitrifying bacteria. N2 isn’t very reactive so the amount of N2 in the atmosphere increased because it was being made but not broken down. Next green plants evolved over most of the Earth as they photosynthesised they removed CO2 and produced O2 (say increased and decreased … )
the amount of O2 in the air gradually built up and much of the CO2 got locked up in fossil fuels and sedimentary rocks

the build up of oxygen in the atmosphere killed off early organisms and allowed the evolution of more complex organisms that made use of the oxygen
the oxygen also made the ozone layer which blocked harmful rays from the sun and enabled more complex organisms to evolve
virtually no CO2 left now

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is the test for chlorine

A

damp blue litmus paper turns red then bleach white

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is the test for ammonia

A

red litmus paper turns blue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

ionic bonding

A

electron transfer / attraction of ions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

covalent bonding

A

shared pairs of electrons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what should you always do when drawing an ionic bond diagram and covalent diagram

A

ionic - all shells and square brackets

covalent - dots and cross and only outer shell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

discuss covalent bonding

A

strong covalent bonds but a weak intermolecular force between these pairs of covalent bonds meaning it has a low mp and bp

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

discuss ionic bonding

A

high mp and bp as it has lots of bonds and needs lots of energy to break every bond and the forces between the positive and negative ions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

discuss fractions at the top of the fractional distillation column

A
  • short chains
  • most useful
  • highly flammable
  • less viscous
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

how do we make the longer chains more useful

A

crack them over an aluminium catalyst into shorter chains

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

word equation for complete combustion

A

oxygen + methane -> CO2 + water

blue flame

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

word equation for incomplete combustion

A

methane -> carbon + carbon monoxide + water + carbon
yellow flame
soot from carbon
carbon monoxide binds to haemoglobin so you can’t carry oxygen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what things speed up the rate of reaction and why

A
  • catalyst (lowers the activation energy and balances out the use of low temperatures)
  • pressure increase (means a smaller space so more collisions take place)
  • increase in surface area (more surface for reactions to take place on)
  • increases in temperature for more energy
  • increase in concentration means more particles to collide
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Endothermic

A

Bond breaking

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Exothermic

A

Bond making

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Which are the most reactive in group 7

A

The elements at the top because it is easier to attract an electron because there isn’t as many shells between the other electron shell and the nucleus

But as you go down there is more shielding and the atoms become less reactive because it gets harder to attract the electron - larger atomic radius

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What happens to the reactivity of the atoms in group 1

A

As you go down group 1 the alkali metals get more reactive. The outer electron is more easily lost because it’s further from the nucleus - large atomic radius - so its less strongly attracted to the nucleus and less energy is needed to remove it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

homologous series

A
  • same functional groups
  • similar properties
  • same general formula
21
Q

5 alkanes and alkenes

A 
my enormous penguin bounces pretty high 
methane 
ethane 
propane 
butane 
pentane 
methane
ethene
propene
butene
pentene
22
Q 
what colour do these go in the flame test
lithium
sodium
potassium
calcium
copper
A 
Li + red
Na+ yellow
K+ lilac 
Ca2+ orange-red
Cu2+ blue-green
23
Q 
what colour do metal hydroxides go that are insoluble and precipitate in reaction when you add sodium hydroxide solution
aluminium 
calcium
copper
iron II
iron III
A 
Al3+ white then a colourless solution in excess 
Ca2+ white
Cu2+ blue 
Fe2+ green
Fe3+ brown
24
Q

test for the halide ions

A

dilute nitric acid and silver nitrate 2ml each
chlorine - white
bromine - cream
iodine - yellow

25
Q

test for carbonates

A

add some dilute nitric acid if there are carbonate ions present the mixture will fizz because the carbonate will react with the acid to produce carbon dioxide gas
to check the gas is carbon dioxide bubble it through limewater and it will go cloudy or milky

26
Q

test for sulfate ions

A

add some dilute hydrochloric acid to the test sample to stop any precipitate reactions not involving sulphate ions from taking place
then add some barium chloride solution and if there are sulphate ions a white precipitate will form of barium sulphate

27
Q

what are the formulas of the first 5 alkanes

A

methane - CH4
ethane - C2H6
propane - C3H8
butane - C4H10

28
Q

what are the formulas of the first 5 alkenes

A

ethene - C2H4
propene - C3H6
but-1-ene - C4H8 (double bond at the end)
bute-2-ene - C4H8 (double bond in the middle)

29
Q

what is the general formula of alkanes

A

CnH2n+2

30
Q

what is the general formula of alkenes

A

CnH2n

31
Q

what are the differences between alkanes and alkenes

A

alkanes:

  • saturated
  • single bonds

alkenes:

  • unsaturated
  • double bonds
32
Q

what is the test for alkanes and alkenes and the positive result

A

bromine water

  • alkanes stay orange
  • alkenes go colourless because the double bond opens up and reacts
33
Q

what are the properties and uses of poly(ethene)

A

properties:

  • flexible
  • electrical insulators
  • cheap

uses:

  • plastic bags
  • bottles
  • wire
  • insulation
34
Q

what are the properties and uses of poly(propene)

A

properties:

  • flexible
  • strong
  • tough
  • mouldable

uses:

  • crates
  • furniture
  • ropes
35
Q

what are the properties and uses of poly(chloroethene) or PVC

A

properties:

  • tough
  • cheap

uses :

  • window frames
  • water pipes
36
Q

what are the properties and uses of poly(tetrafluoroethene) or PTFE

A

properties:

  • unreactive
  • tough
  • non stick

uses;

  • non-stick pans
  • waterproof clothing
37
Q

how do you draw a diagram of addition polymerisation

A

undo the double bond and put one bond then put the formula diagram in square brackets with the ends of the carbon with sticks over the edge
add an n or the number of monomers

addition polymers have a double covalent bond

38
Q

polymers

A

are substances of high average relative molecular mass made by joining up lots of small repeating units called monomers

39
Q

condensation polymerisation

A

two different types of monomers
at least two functional groups one at each end
for each new bond that forms a small molecule is lost normally water

dicarboxylic acid monomers contain two carboxylic acid (-COOH) groups
diol monomers contain two alcohol (-OH) groups
when the carboxylic acid group reacts with the alcohol group it forms and ester link and every time this happens water is lost

40
Q

what are three naturally occurring polymers

A

DNA - nucleotide monomers that bond together in a polymerisation reaction

Amino acids- monomers from polymers proteins via condensation polymerisation

carbohydrates - molecules containing carbon, oxygen and hydrogen used by living things to produce energy

Starch and Cellulose are large complex carbohydrates which are made of small units of carbohydrates known as sugar in a long chain

41
Q

what is empirical formula

A

the simplest ratio of atoms

42
Q

find the empirical formula of glucose C6H1206

A

the numbers in the molecular formula of glucose are 6, 12 and 6
to simplify the ration divide them by the largest that goes into all three which is 6
C: 6/6 = 1
H: 12/6 =2
O: 6/6 = 1
The empirical formula of glucose is CH2O

43
Q

a sample of hydrocarbon contains 36g of carbon and 6g of hydrogen, work out the empirical formula of the hydrocarbon

A 
moles = mass / Mr 
work out how many moles of each element you have 
C: 36/12 = 3 moles 
H: 6/1 = 6moles 
now divide both numbers by the smallest 
3/3 =1
6/3 = 2
CH2
44
Q

what happens when the halogens (group 7) react with metals and hydrogen

A

they from a salt called a metal halide

soluble and dissolve in water to form acidic solutions

45
Q

what are the halogen displacement reactions

A

redox reactions
the halogens gain electrons which is reduction
higher up group 7 the more reactive and will displace atoms in the reactions

46
Q

rate of reaction equation

A

amount of reactant used or product formed over time

47
Q

discuss the precipitation reaction to follow rate of reaction

A

you mix the two reactant solution and put the flask on a piece of paper that has an X on it
observe the mark through the mixture and observe how long it takes for the mark to be obscured, the faster it disappears the faster the reaction
but the result Is subjective

48
Q

discuss the change in mass practical to follow rate of reaction

A

as the gas is released the lost mass is easily measured on the mass balance

Chemistry (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions