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Science > Chemistry Paper 2 > Flashcards

Chemistry Paper 2 Flashcards

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1
Q

practical

describe how to measure how surface area affects rates of reaction in a gas

4 marks

A
  1. attach a gas syringe to a chronical flask containing CO2 + HCl + marble chips
  2. measure volume of gas with syringe at regular intervals
  3. Repeat with the same volume and concentration of acid and mass of marble chips but just more crunched up
  4. repeat with same mass but instead of chips uses powdered chalk and make a graph of your results
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2
Q

what should you see when you are measuring how surface area or acid concentration affects rate of reaction of a gas? (2)

A
  • the higher the surface area the faster the rate of reaction
  • the higher the acid concentration the faster the rate of reaction
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3
Q

practical

describe how you would test to see how temperature affects the rate of reaction in a precipitation reaction?

3 marks

A
  1. measure out fixed volumes of sodium thiosulfate, hydrochloric acid and heat it using a water bath
  2. put flask over a black marker and watch the marker slowly disappeared due to the solution going cloudy
  3. repeat at different temperatures but with the same volume and concentration then make a graph of your results
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4
Q

what should you see when you are measuring how temperature affects rate of reaction of a precipitation reaction?

1 mark

A
  • the higher the temperature the faster it takes to go cloudy (marker disappears)
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5
Q

what is the between endo and exothermic reactions? (2)

A

endothermic -> takes in energy
exothermic -> gives out energy

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6
Q

how does a catalyst affect the activation energy? (1)

A
  • It decreases the activation energy
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7
Q

what is activation energy? (1)

A
  • amount of energy needed to start a reaction
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8
Q

practical

how would you find the temperature change of 2 reagents?

6 marks

A
  1. put a polystyrene cup in a beaker of wool (for insulation)
  2. add a known volume of first reagent (mixture)
  3. measure intitule temperature then add known mass of second reagent and stir
  4. put lid on to reduce energy loss
  5. record max or minimum temperature (depending if it increased or decreased
  6. calculate temperature change
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9
Q

which one of these soluble salts is exothermic and which is endothermic? (2)
- ammonium chloride
- calcium chloride

A
  • ammonium chloride -> endothermic
  • calcium chloride -> exothermic
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10
Q

are displacement and precipitation reactions exothermic or endothermic (1)

A
  • exothermic
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11
Q

what is the formula for: (4)
- methane
- ethane
- propane
- butane

A
  • CH4
  • C2H6
  • C3H8
  • C4H10
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12
Q

what is the order of hydrocarbons from the highest boiling point to the lowest in the fractional distillation chamber?

6 marks

and what are they used for?

A
  1. bitumen (for roads)
  2. fuel oil (ships)
  3. Diesel (trucks)
  4. kerosene (jets)
  5. petrol (cars)
  6. gases (heating/cooking)
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13
Q

the higher up the distillation chamber the…?

4 marks

A
  • easier the ignite
  • shorter the hydrocarbon
  • lower the viscosity
  • lower the boiling point
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14
Q

how does fractional distillation work in terms of hydrocarbons? (4)

A
  • crude oil gets put into a chamber and heated to a very high temperature
  • then it is put in the fractional distillation chamber and at each level, it gets colder
  • as it gets colder the hydrocarbons condense and get separated into different lengths
  • this allows the hydrocarbons to be used for their purposes
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15
Q

what is crude oil? (1)

A
  • a complete mixture of different hydrocarbons
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16
Q

what is the problem with carbon monoxide and how is it made? (3)

A
  • binds to red blood cells stopping them from carrying oxygen
  • lack of oxygen causes fainting/death
  • incomplete combustion
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17
Q

what is the problem with sulfur dioxide (SO2) and how is it made? (3)

A
  • Its realised from impurities of fossil fuels
  • it mixes with the clouds causing acid rain
  • this kills life and damages the environment
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18
Q

what is the problem with oxides of nitrates and how is it made? (4)

A
  • created by nitrogen reacting with oxygen in the air
  • only happens because of the energy released from combustion
  • it contributes to acid rain
  • and causes photochemical smog -> causing breathing difficulties
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19
Q

What are the pros and cons of using hydrogen as clean energy?

A

pros -> very clean + renewable (from water)
cons -> needs special expensive engine + needs lots of energy + hard to store

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20
Q

what is cracking? (3)

A
  • splitting up long-chain hydrocarbons to get shorter, more useful ones
  • uses thermal decomposition (breaking down into 2 or more things)
  • needs lots of energy as it needs to break a strong covalent bond
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21
Q

how would you do a craking reaction? (3)

A
  • vapourised hydrocarbon is passed over a powdered catalyst at 400 - 700 degrees and 70 atm
  • Aluminium oxide = catalyst - the long molecules split apart on the surface of catalysts
  • alkane is heated until vaporised
    e.g (C10H22 -> C8H18 + C2H4)
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22
Q

why do we do craking? (2)

A
  • shorter hydrocarbons are much more useful than longer ones
  • demand for shorter hydrocarbons are higher than amount so we can turn the longer ones into shorter ones
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23
Q

how does warmth get to the earth? (3)

A
  1. The sun emits electromagnetic radiation
  2. some pass through the atmosphere
  3. shorter wavelengths get absorbed -> warming up the planet
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24
Q

how does the greenhouse effect work? (5)

A
  1. earth radiates some heat radiation
  2. greenhouse gasses absorb some IR radiation
  3. some IR is re-emitted back towards earth by greenhouse gasses
  4. some IR is re-emitted back into space
  5. greenhouse gasses keep the Earth warm
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25
Q

what was the first phase of the atmosphere? (4)

A
  1. started with a molten surface
  2. volcanoes kept erupting releasing CO2, steam, methane and ammonia
  3. this settled down leaving the atmosphere mostly CO2 and water vapor
  4. later water vapour condensed to form oceans
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26
Q

what was the second phase of the atmosphere? (5)

A
  1. lots of CO2 dissolved into oceans
  2. nitrogen gas formed
  3. N2 increased as it isn’t reactive so it didn’t get broken down
  4. green plants evolved by removing CO2 and producing O2
  5. CO2 got locked up in fossil fuels and sedimentary rocks
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27
Q

what was the third phase of the atmosphere? (4)

A
  1. oxygen killed off early organisms
  2. allowed evolution to make complex organisms
  3. oxygen made the ozone layer (O3) that blocks harmful sun rays -> so more complete organisms can form
  4. almost no CO2 was left
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28
Q

what colours do flames go in these metal ions? (5)
1. lithium
2. sodium
3. potassium
4. calcium
5. copper

A
  1. red
  2. yellow
  3. lilac
  4. orange
  5. green/blue
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29
Q

what are the colours of these precipitates? (5)
1. AL3+
2. Ca2+
3. Cu2+
4. Fe2+
5. Fe3+

A
  1. white (in excess NaOH -> colourless)
  2. white
  3. Blue
  4. Green
  5. Broun
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30
Q

how do you find out the metal of an insoluble metal hydroxide? (2)

A
  1. put sodium hydroxide (NaOH) solution into the mystery compound
  2. if hydroxide precipitate forms match the colour is the characteristic colour of metal precipitates to figure out what on it is
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31
Q

how do you work out if a substance contains ammonium ions? (5)

A
  • add sodium hydroxide and heat
  • if ammonia gas is given off that means it has ammonium ions
  • you test for ammonia gas by holding damp red litmus paper over it
  • If it is ammonia it will go blue
  • it also has a bad smell but don’t smell it as it is an irritant and toxic
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32
Q

how do you test for chlorine/bromide/iodine ions?

2 marks

A
  • add some dilute nitric acid (HNO3)
  • add silver nitrate solution (AgNO3)
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33
Q

what colours do these ions go when testing for anions? (3)
- chloride
- bromide
- iodide

A
  • chloride -> white
  • bromide -> cream
  • iodide -> yellow
34
Q

how do you test for carbonates? (3)

A
  • add dilute acid
  • if there present mixture will fizz because it produces CO2
  • you can check a gas is CO2 by bubbling it though limewater -> it will go cloudy
35
Q

how do you test for sulfate ions?

3 marks

A
  • add dilute hydrochloric acid (to stop precipitstion reactions not involving sulfate ions from taking place)
  • then add barium chloride solution
  • if there are sulfate ions a white precipritate will form
36
Q

what is flame photometry?

2 marks

A
  • an instrumental method that allows you to identify ions in a dilute solution
  • each ion produces a unique line spectrum
37
Q

what does the intencity of the measured wavelength indicate of photometry and how?

2 mark

A
  • the consentration of the ion
  • using a calibration curve
38
Q

what are the addvantages of using machines of flame photometry?

3 marks

A
  • very sensitive
  • very fast
  • very acurate
39
Q

what is a homologous series?

1 mark

A

a group of chemicals that have a simular chemical structure
e.g. alkanes are a homologous series of hydrocarbons

40
Q

which have a double bond?
- alkenes or alkanes

1 mark

A
  • alkenes
41
Q

how do you test for alkenes?

2 marks

A
  • shake in bromine water
  • it will decolourise the bromine (orange -> colourless) as it is an addition reaction
42
Q

what are polymers?

3 marks

A
  • substances of high average relative molecular mass
  • lots of joined monomers
  • monomers that make up addition polymers have a double covalent bond
43
Q

what is addition polymerisation?

1 mark

A
  • unsaturated monomer molecules open their double bond and join together to form polymer chains
44
Q

what are the uses of these polymers?

  • poly(ethene)
  • poly(propene)
  • poly(chlorethene)
  • (PTFE)

4 marks

A
  1. plastic bags/insulation (flexible)
  2. furniture (strong)
  3. pipes (tough)
  4. waterproofs (unreactive)
45
Q

what is condensation polymers?

3 marks

A
  • involves 2 types of monomers to make a polymer
  • monomers bond together making a chain containing at least 2 funtional groups
  • this makes a chain of alternation polymers
46
Q

what makes a polyesters

3 marks

A
  • when a dicarboxylic acid and diol monomer react
  • dicarboxylic acid monomers contain 2 carboxylic acid
  • diol monomers contain 2 alcohols (-OH)
47
Q

what happens when a ester link is formed?

1 mark

A
  • a molecule of water is lost
48
Q

what are the natural occuring polymer and how they made?

6 marks

A
  • DNA -> made from 4 nucleotides
  • protein -> amino acid
  • carbonhydrates -> containing carbon and oxygen
49
Q

describe landfill

3 marks

A
  • due to polymers being expencive to dispose they go into to ground
  • lots of valuble land gets used up
  • most polymers are non-biodegradable so they dont get broken down in the ground
50
Q

describe disposable by combustion

3 marks

A
  • burning plastics produse energy
  • if not controled -> gas produced can be toxic
  • CO2 is also prodused going towards globle warming
51
Q

what are the advantages of recycling polymers?

5 marks

A
  • reduces waste in landfill
  • reduces greenhouse gas emissions
  • uses less energy then making new ones
  • reduces need for crude oil
  • saves money and makes jobs
52
Q

what are the disadvantages of recycling polymers?

4 marks

A
  • difficult / expensive to separate as they need to be melted and reformed
  • quality can be reduced
  • can only be recycled a finite amount as it losses strength
  • melting them can release dangerous gases that are harmful to plants and animals
53
Q

what is alcohols funtional group?

1 mark

A

-OH

54
Q

what is the general formula for alcohol?

1 mark

A

C(n)H(2n+1)OH

55
Q

how can alcohols be oxidised?

1 mark

A
  • using oxidising agent to form carboxylic acid
56
Q

what is the general formula for carboxylic acids?

1 mark

A

C(n-1)H(2n-1)COOH

57
Q

what is fermentation?

2 marks

A
  • process that uses yeast to convert carbohydrates (sugars) into alcohol
  • C6H12O6 –> 2C2H5OH +2CO2
58
Q

where does carbohydrates come from?

2 marks

A

sugar cane and sugar beet

59
Q

practical

how would you make a solution of ethanol from fermentation?

5 marks

A
  • mix yeast and carbohydrates and seal the container putting it in a warm place
  • keep between 30-40 degrees for enzymes
  • keep away from oxygen as if reacted with it will turn to ethanolic acid(vinegar)
  • when concentration of alcohol gets to 10%->20% it stops as yeast gets killed of by alcohol
  • yeast goes to bottom and ethanol solution goes to the top
60
Q

concentration of alcohol:

  1. beer
  2. spirits

2 marks

A
  1. 4%
  2. 40%
61
Q

how is fractional distillation used to concentrate ethanol?

4 marks

A
  1. a dilute solution is produced though fermentation
  2. above 20% you must use fractional distillation
  3. ethanol has a lower boiling point so ethanol get evaporated first
  4. after its evaporated out of water it condences and can be collected
62
Q

practical

how can alcohol be used to heat water and find out which one is the best for specific volume of water?

7 marks

A
  1. put alcohol into spirit burner and measure mass of the burner and fuel with electronic balance
  2. measure 100cm3 distilled water into copper calorimeter
  3. insulate meter with draught excluder and cover with insulating lid after putting thermometer inside
  4. take initial temperature and light the wick
  5. stir throughout until its 20 degrees hotter then blow out
  6. re measure mass of burner and fuel
  7. repeat using other alcohols with keeping everything else the same
63
Q

what are the control varibles of a alcohol experiment?

4 marks

A
  • mass/vol of water
  • height above wick
  • length of wick
  • moles of alcohol
64
Q

what is a nanopartical?

2 marks

A
  • a tiny particles between 1-100 nanometres (0.000,000,001m)
  • only contain a few hundred atoms
65
Q

what are fullerenes?

2 marks

A
  • nanopartiles
  • includes nanotubes (strong, tiny hollow carbon tubes)
66
Q

what happens when a particle decreases in size?

1 mark

A

surface area:volume increases

67
Q

how do you work out surface area:volume?

1 mark

A

surface are:volume = surface area / volume

68
Q

how can nanoparticles modify properties of maturials?

7 marks

A
  • huge surface area to volume ratio so they make a good catlalyst because more colitions will take place
  • sunscreens use them as they protect you without leaving marks on skin
  • nanomedicine can allow drugs to be absorbed into body straight to where its needed
  • lubricant coating using fullerenes can be used in gears
  • can be used in computer chips as they conduct electricity
  • they make plastics stronger so it is good sports equipment
  • silver nanoparticles are used in masks giving antibacterial properties
69
Q

how do nanoparticles effect our health

3 marks

A
  • it isnt fully understood so its important to be tested
  • people worry products havent been tested properly and could be harmful long term
  • some nanoparticles dont break down and can cause lung inflammation
70
Q

what are these polymers used for?

  1. strong and rigid
  2. light and stretchy
  3. foam
  4. heat resistant

4 marks

A
  1. water pipes
  2. bags and bottles
  3. thermal insulators
  4. kettles
71
Q

how is clay formed and whats a good use?

2 marks

A
  1. weathered and decomposed rock is dug out ground and moulded into shape(pottery/bricks)
  2. its hardened in high temperatures making a good building block that can withstand a high weight
72
Q

how is glass formed?

3 marks

A
  1. this transparent maturial is moulded when hot and is brittle when thin
  2. made from heating limestone, sand and sodium carbonate until they melt
  3. when cooled it becomes glass
73
Q

what is carbon fiber?

3 marks

A
  • carbon bonded together
  • or carbon nanotubes held together
  • they are expensive but strong and light (good for aaerospace)
74
Q

what are the properties of polymers?

5 marks

A
  • flexible
  • easily moulded
  • cheap
  • thermal and electrical insulators
  • can degrade and break down
75
Q

what are the properties of ceramics?

4 marks

A
  • insulators
  • brittle and stiff
  • strong and hard
  • dont degrade or corrode
76
Q

what are the properties of metals?

5 marks

A
  • good conductors of heat/electric
  • malleable
  • some corrosion resistant some not
  • less brittle
  • can deform
77
Q

what are the properties of composites?

3 marks

A
  • depends on matric and reinforcement
  • designed for specific purpose
  • can be expencive
78
Q

what is the equation for rate of reaction?

1 mark

A

amount formed / time

79
Q

what is the equation for overall energy change?

1 mark

A

energy to break bond - energy released to form bond

80
Q

whay is the equation of combustion?

1 mark

A

hydrocarbon + oxygen –> carbon dioxide + water

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