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Paper 2 Flashcards

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1
Q

What’s rate of reaction

A

How fast reactants are changed into products

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2
Q

Examples of slow reactions

A

Rusting iron and chemical weathering

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3
Q

Give an example of a fast reaction

A

Burning and explosions which can be a fraction of a second

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4
Q

How can you use a graph to show the rate of reaction?

A

The steeper the graph the faster, you’ll also recognise the graph will level off as the reactants are used up.

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5
Q

Using collision theory explain rate of reaction

A

The more collisions the faster the reaction is, despite this particles must collide with enough energy for the collision to be successful.

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6
Q

Factors increasing the number of collisions are?

A

Increasing surface area, concentration and temperature. Also using a catalyst

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7
Q

Why does temperature increase the rate of a reaction

A

The particles move faster because thermal energy transfers to kinetic energy therefore more collisions will occur and they’ll have the energy to be successful.

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8
Q

Why does concentration or pressure increase the rate of a reaction?

A

Concentration - There’s more particles “knocking about” in the same volume of solvent. Pressure - The same number of particles in a smaller space. This both cause more FREQUENT collisions between the reactants.

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9
Q

How does increasing surface area increase the rate of reaction?

A

Increases surface area to volume ratio, therefore despite being the same volume, there’s more area to work on therefore more frequent collisions.

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10
Q

How does adding a catalyst increase rate of reaction?

A

Catalysts speed up a reaction without being “used up” therefore it’s not included in the reaction equation. Different catalysts work for different reactions - They work by decreasing the activation energy needed for the reaction to occur by providing an alternative pathway with a lower activation energy.

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11
Q

What is a biological catalyst?

A

Enzymes - Catalyse reactions in living things

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12
Q

How to calculate mean rate of reaction?

A

Amount of reactant used r amount of product formed divided by time

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13
Q

How to calculate rate of reaction at a particular time?

A

Draw a tangent at that time then do the calculation.

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14
Q

What’s the unit for products and reactants ?

A

Gas = Centimetre3
Solid = Grams
Time = Seconds
This means the units for rate of reaction is cm3/s or g/s.
You can also use moles so could be mol/s.

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15
Q

3 ways to measure rate of reaction

A

Precipitation/colour change
Change in mass
Volume of gas given off

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16
Q

What’s turbidity

A

Cloudiness of a solution changes

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17
Q

Describe using precipitation and colour change to measure rate of reaction

A

Observing a visual change. You can observe a mark through the solution and see how long it takes to disappear - precipitation. For colour change place on a white tile and see how long it takes to lose or gain its colour. The issue is its subjective and you can’t mark the rate of reaction on a graph

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18
Q

How can you use change in mass to measure rate of a reaction.

A

Using a mass balance and weighing the reactants decreasing in mass (usually a gas given off) Taking measurements at regular intervals and plotting into a graph. This is most accurate of measuring rate of reaction. Disadvantage - Releasing gas into room which could be potentially dangerous

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19
Q

How can you use volume of gas given off to measure rate of reaction?

A

You can either measure through a gas syringe or counting bubbles - which will be less accurate.

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20
Q

What does magnesium and hydrochloric acid react to form?

A

H2 Gas

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21
Q

What does sodium this sulphate and HCL produce?

A

A cloudy precipitate - sulfur dioxide

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22
Q

In a closed system what will a reversible reaction reach?

A

Dynamic equilibrium - Nothing can be lost or gained to the reaction therefore both reactions continue to happen at the same pace and there’s no overall effect.

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23
Q

Describe position of equilibrium

A

If it lies to the right the concentration of products is greater than reactants.
If it lies to the left the concentration of reactants is greater than products.

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24
Q

What effects position of equilibrium?

A

Temperature
Pressure (Gas)
Concentration

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25
What does anhydrous mean?
‘Without water’
26
What happens if you change temperature in equilibrium?
Decrease temp = It’ll move to the exothermic direction to produce more heat Increase temp = It’ll move to the endothermic direction to decrease the heat. This means it’ll produce more products in that direction.
27
How does pressure affect equilibrium ?
Increase pressure = Moves to direction where there’s few molecules of gas to reduce pressure Decrease pressure = Moves to direction where there’s more molecules of gas to increase pressure Using a balanced symbol equation you can figure out which side has more molecules of gas
28
How does concentration affect equilibrium?
Increase concentration of reactants = Makes more products Decrease concentration of products = Reduce amounts of reactants
29
How would you investigate the effect of increasing HCL on the rate of reaction between HCl and Mg?
Seeing the change of mass
30
How can you measure the reaction between sodium thiosulfate and HCl ?
Colourless to yellow precipitate (sulfur dioxide)
31
What’s a compound formed from hydrogen and carbon atoms only
A hydrocarbon
32
What’s the general formula of alkanes
CnH2n+2.
33
What bonds are alkanes?
Single C-C bonds
34
What series and compounds are the alkanes
Homologous series - They all react in a similar way Saturated compounds - Each carbon atom forms four single covalent bonds
35
What’s the first four alkanes and their chemical formula
Methane CH4 Ethane C2H6 Propane C3H8 Butane C4H10
36
How do the properties of hydrocarbons change?
The length of the chain changes the properties. The shorter the chain it is: More runny it is (less viscous) Lower boiling point (more volatile) The more flammable (easier to ignite)
37
The properties of hydrocarbons change how they’re used for fuels. Describe how this works
The shorter chains are used as bottled gases because of their lower boiling point. - Stored under pressure as liquids in bottles.
38
Describe complete combustion of hydrocarbons in oxygen
Waste products are carbon dioxide and water vapour. They require lots of oxygen. It releases lots of energy. Both carbon and hydrogen from the hydrocarbon are oxidised.
39
What’s crude oil?
It’s a fossil fuel formed over a long amount of time - remains of plants and animals with high pressure and heat. These can be drilled up from rocks where it’s found. This is a non renewable finite resource
40
What separation method is used to separate hydrocarbon formula
Fractional Distillation
41
Describe the fractional distillation of crude oil
At the bottom of the column is the hottest, the top is the coolest, the mixture of hydrocarbons have different boiling points depending on length (the shorter the lower) this then separates the hydrocarbons as the different hydrocarbons will condense and drain out later on than others.
42
What’s the hydrocarbons extracted from crude oil
From highest boiling point to lowest : Bitumen Heavy fuel oil (lubricating, fuel or heating oil) Diesel oil (car/lorry fuel) Kerosene (plane fuel) Petrol (car fuel) LPG (petroleum gas - gas camping fire- mostly contains propane and butane)
43
What’s some uses of crude oil? - once being broken up?
Transport fuels, Burning fuels for cooking and heating and making new compounds such as polymers,solvents,lubricants and detergents
44
What’s cracking?
Splitting up long chain hydrocarbons
45
Whats different methods of cracking?
Thermal decomposition - breaking down molecules by heating them. One way is by heating the long chain hydrocarbon and vaporising them which is then passed over a hot powdered aluminium oxide catalyst where the long chain molecules will split apart on the surface of the specks of catalyst - CATALYTIC CRACKING Or you can vaporise them and mix them with steam and then heat them to a very high temperature - STEAM CRACKING
46
What’s polymerisation and what does it require?
Joining of monomers to form polymers (Plastics) through high pressure and a catalyst
47
What’s are plastics made up of
Polymers which are usually carbon based and their monomers and often alkenes
48
What are addition polymers made up of?
Unsaturated monomers
49
Whats the unsaturated monomer of hydrocarbon
Alkenes - the unsaturated means they have a double carbon carbon bond
50
What’s the general formula for alkenes?
CnH2n
51
Out of alkanes and alkenes which is more reactive and why?
Alkenes because of their double bond can open up to become single and that bond can react with other atoms
52
What’s the first 4 alkenes and their chemical formula?
Ethene C2H4 Propene C3H6 Butene C4H8 Pentene C5H10 When drawing them remember that only the middle 2 carbons have a double bond and the rest are single therefore that’s the only bond that can open up and form 2 single bonds which make the alkenes reactive Also put the 2 extra carbon bonds on the end of the chain when you draw them
53
Why does incomplete combustion occur instead of complete combustion in the combustion of alkenes?
There’s not enough oxygen in the air
54
Whats the equation for incomplete combustion in alkenes?
Alkene + oxygen — carbon dioxide + water + carbon monoxide If this was complete combustion of alkenes then carbon monoxide would not be released
55
What’s the visible result of incomplete combustion?
A smoky yellow flame.
56
EXAMPLE - Chemical equation of incomplete combustion of butane where there’s 5 molecules of oxygen in the reactants
C4H8 + 5O2 — 2CO + 2CO2 + 4H2O
57
EXAMPLE - Chemical equation of incomplete combustion of butane where there’s 5 molecules of oxygen in the reactants
C4H8 + 5O2 — 2CO + 2CO2 + 4H2O
58
What a functional group
A group of atoms in a molecule that determine how a molecule typically reacts
59
Whats the functional group of alkenes
C=C
60
What’s the reaction of addition of hydrogen?
Hydrogenation
61
What is hydrogenation
The addition of hydrogen to a molecule In the hydrogenation of alkenes the hydrogen reacts to form a saturated alkene as the double bond opens up and joins to the hydrogen. This happens in the presence of a catalyst
62
What occurs when steam reacts with alkenes
Alcohol is formed
63
Describe how using steam ethanol can be formed through ethene
Mixing ethene and steam and passing this over a catalyst ethanol will form. After this the reaction mixture is passed from the reactor into a condenser. Ethanol and water have a higher boiling point than ethene therefore they both condense whilst any unreacted ethene gas is recycled back into the reactor. The alcohol can then be purified through fractional distillation.
64
How do halogens react with alkenes?
They form an alkane for example ethene and bromine form dibromoethane
65
How to test for alkenes using bromine water
By putting orange bromine water with a saturated compound like a alkane no reaction will occur and the mixture will remain bright orange. Whereas if you place it with an alkene bromine will add across the double bond and make a colourless dibromo-compound so the bromine is decolourised
66
Whats the functional group of alcohol
-OH and they end in ‘-ol’
67
What’s the first 4 homologous series of alcohol
Methanol CH3OH Ethanol C2H5OH Propanol C3H7OH Butane’s C4H9OH
68
Whats some typical properties of alcohols
Flammable When undergoing complete combustion they produce carbon dioxide and water When oxidised they produce carboxylic acid React with sodium and produced hydrogen
69
Why are alcohols used as solvents and fuels?
Solvents: Dissolve things that water cant dissolve Fuels: Flammable
70
What’s the equation for fermentation?
Sugar - (yeast) - ethanol + carbon dioxide
71
Whats the temperature fermentation occurs best
37
72
Whats the conditions that fermentation requires
37 degrees (FASTEST) Yeast enzyme present Slightly acidic conditions Anaerobic conditions (no oxygen)
73
What’s the functional group of carboxylic acid
- COOH So a carbon atom with a double bond to an oxygen and then a single bond to OH
74
How do carboxylic acids act?
With carbonates they produce salt, water and carbon dioxide When dissolved in water they ionise and release H+ ions resulting in an acidic solution
75
Whats the functional group of esters
-COO-
76
How are esters formed?
An alcohol and a carboxylic acid Usually use an acid catalyst It also produces water
77
Whats condensation polymerisation
Involves monomers that have different functional groups. For every new bond made a small molecule is lost hence why it’s called condensation polymerisation. The simplest type of condensation polymers contain 2 different types of monomers - each with 2 of the same functional group
78
Compare the number of types of monomers, number of products and functional groups involved in addition and condensation polymerisation
ADDITION- Only one monomers type which contains a C=C bond. Only one product formed Carbon-carbon double bond in monomer CONDENSATION - 2 monomer types each contacting two of the same function groups OR one monomer type with different functional groups 2 types of products formed - polymer and a small molecule (eg:water) 2 reactive groups on each monomer
79
What groups are amino acids made from
Amino group and carboxyl group
80
The formulaic equation for metals formed in a coloured precipitate with NaOH
(METAL)(x)+ + (x)OH- (arrow) Ca(OH)(x)
81
Whats a pure substance
A compound or element with nothing else mixed into it
82
How does being impure change the melting and boiling point of a substance ?
Increases the range of both Impure increases boiling point and decreased boiling point
83
Whats a formulation
Useful mixtures precisely measured for a specific purpose.
84
Examples of formulations
Pharmaceutical industry Cleaning products Food and drink Makeup Fertilisers
85
Whats the 2 phases in chromotography
Mobile phase - where the molecules move - always a liquid or gas Stationary phase - where the molecules can’t move - a solid
86
How to calculate Rf value
Distance travelled by substance divided by distance travelled by solvent
87
Positive test result for chlorine, oxygen, carbon dioxide and hydrogen
Chlorine: Bleaching damp litmus paper Oxygen: Relight a GLOWING splint Carbon dioxide: Bubbling it through limewater and it becoming cloudy Hydrogen: Holding a lit splint over test tube and a squeaky pop occuring
88
Tests for anions
Using dilute acid to detect carbonates - add dilute acid to test tube and running it through limewater - positive result will be cloudy Using HCl and Barium chloride to test for sulfates - Add barium chloride and HCl drops to the test tube and if its a positive result it will form a positive precipitate
89
Testing for halides
Adding nitric acid and silver nitrate to your mystery solution. Chloride - white precipitate of silver chloride Bromide - cream precipitate of silver bromide Iodide - yellow precipitate of silver iodide
90
Colours of the flame tests of cations Lithium Sodium Potassium Calcium Copper
Lithium - Crimson Sodium - Yellow Potassium - Lilac Calcium - Orange/red Copper - Green
91
Colours of precipitate formed with sodium hydroxides forming insoluble hydroxides: Calcium Copper (II) Iron (II) Iron (III) Aluminium Magnesium
Calcium - white Copper (II) - Blue Iron (II) - Green Iron (III) - Brown Aluminium - White then colourless Magnesium - White
92
What’s the benefits of using instrumental analysis ?
Very sensitive Very fast Very accurate
93
Functional group of carboxylic acids
COOH
94
How do we obtain nitrogen for the haber process
Fractional distillation of the liquified air
95
How do we obtain hydrogen for the haber process
Methane and steam at a high temperature
96
What temperature, pressure and catalyst is used in the haber process
450 degrees 200 atmopsheres Iron
97
What the equation for the haber process
N2 + 3H2 (reversable arrow) 2NH3
98
Which direction is the exothermic/endothermic reaction in the haber process
Exothermic is to the right Endothermic is to the left
99
If you increase the temperature of the haber process what happens to the rate and yield and equilibrium
Rate increases Yield decreases Equilibrium moves to the left
100
If you increase pressure of the haber process what happens to the rate and yield and equilibrium
Rate increases Yield increases Equilibrium moves to the right
101
If you remove the products what happens to the yield, rate and equilibrium
Moves to the right Increases yield and rate
102
If you add a catalyst what happens to the rate, yield and equilibrium
Rate increases Yield remains the same Equilibrium stays the same because it speeds up both reactions
103
How are NPK influencers made?
Neutralization reactions in a lab from ammonia solutions and different aqueous acids. SO neutralize them then meshfec

Chemistry (2 decks)

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