Paper 2 Flashcards
(93 cards)
1
Q
What elements are in the halogens? (Answer in order from top of group to bottom)
A
Fl fluorine (g) Cl chlorine (g) Br Bromine (l) I Iodine (s) At Astatine (?)
2
Q
What group are the halogens in and what does this tell us about them?
A
Group 7
Therefore have 7 electrons in their outer shell
3
Q
What happens to the melting and boiling point as you go down group 7?
A
The melting and boiling point of halogens increase/get higher as you go down the group
4
Q
What happens to the reactivity as you go down group 7 and why?
A
It gets less reactive because they have more shells further down the group and therefore the electrostatic forces of attraction are weaker and electrons are harder to pull in.
5
Q
Halogens exist as diatomic molecules meaning?
A
They only exist as two atoms covalently(shared electrons) bonded together as a molecule. For example,
Fluorine exists as F[2] and chlorine exists as Cl[2]. This is because they both need one more electron to have a full outer shell and therefore can covalently bond
6
Q
Metal + halogen –>
A
Metal halide
E.g Fluorine + magnesium –> magnesium fluorIDE
7
Q
What type of bonding occurs between metals and non metals?
A
Ionic bonding so the metal will give electrons to the non metal and therefor give the non metal a negative charge
8
Q
What are the colours of the halogens? And what is the trend? (As a gas?
A
Fluorine is pale yellow
Chlorine is pale yellow- green
Bromine is orange-brown
Iodine is violet
9
Q
When do halogens take part in displacement reactions?
A
When reacting with halide salts e.g potassium iodide that have a halide that is less reactive than the halogen
10
Q
What is oxidation?
A
Loss of electrons ( e.g bromide ions have lost electrons so have been oxidised to Bromine during the reaction with chlorine and potassium bromide)
11
Q
What is reduction?
A
Gaining electrons e.g chlorine ions gain electrons so have been reduced to Chlorine- ions during the reaction with chlorine and potassium bromide
12
Q
What are group 1 metals called?
A
Alkali metals
13
Q
What are the properties of an alkali metal?
A
- soft/malleable
- low density
- react with water and oxygen
- toxic
- shiny
14
Q
In group 1 what happens to the reactivity as you go down the group?
A
It gets more reactive because there are more shells and therefore the electrostatic forces of attraction are weaker and electrons can be lost easier
15
Q
Where are the group 0 elements located in the periodic table?
A
The far right
16
Q
What are the group 0 elements more commonly known as?
A
Noble gases
17
Q
What is special about the reactivity of the noble gases?
A
They are in reactive due to a full outer shell
18
Q
What are the uses of the group 0 elements?
A
Helium is used in balloons
Radon is used in hospitals for gamma rays
Xenon is used in fluorescent bulbs
19
Q
What elements (in order) are in the group 1?
A
Li lithium Na sodium K potassium Rb rubidium Cs caesium Ft francium
20
Q
What elements are in group 0? In order
A
He helium Ne neon Ar argon Kr krypton Xe xenon Rn radon
21
Q
How many electrons do group 2 elements have in their outer shell?
A
2 dumbass
22
Q
What happens to the reactivity of group 2 elements as you go down the group and why?
A
The reactivity increases because the attraction between the 2 electrons they need to lose and the nucleus grows weaker and therefor can lose those two electrons easier
23
Q
What do all group 2 elements have in common?
A
- all react with water
- have 2 electrons in their outer shell
24
Q
Why can atoms lose electrons easier if they have more shells?
A
Because they have weaker electrostatic forces of attraction
25
How does temperature affect the rate of reaction?
It increases because as the temperature increases, the atoms start to vibrate due to the increase in energy.
This results in more collisions between them and the reactant and therefore more successful collisions
26
How catalysts affect the rate of reaction?
They speed up rates of reaction without getting used up themselves. They do this by lowering the activation energy required, therefore particles don't need as much energy when colliding to react and therefore there are more successful collisions.
27
How does increasing surface area affect the rate of reaction?
It speeds up the reaction by making more particles available to the reactant to react making more collisions and hence, more successful collisions.
28
How does increasing pressure affect the rate of reaction?
It increases because there is an increase in the chance of particles colliding because there is more particles to space available and therefore there more frequent collisions and hence, more successful collisions.
29
How does increasing the concentration affect the rate of reaction?
It increases the rate of reaction as there are mor particles available to react in the same volume so there is a greater chance of the particles colliding and hence more successful collisions.
30
How do you work out rate of reaction?
| Formula
Volume produced/time taken
31
How do you work out average rate of reaction from a graph?
Draw a tangent to the curve
Draw a vertical line and horizontal line to form a right-angled triangle with the line from step 1.
Then do x/y
(Change in volume produced/time)
32
What are the colours of the halogens?
Fluorine - pale yellow
Chlorine- green
Bromine - brown
Iodine - purple
33
What are alcohols?
Alcohols are a family of organic (carbon-based) compounds. They all contain the –OH group and this is generally responsible for their chemical properties and reactions.
34
What are the uses of methanol?
-Methanol can be used as a chemical ‘feedstock’ (starting material for other chemical reactions)
-in anti-freeze and in the production of biodiesel.
.
35
What are the uses ethanol?
Ethanol can be used as a solvent and as a fuel
36
What are the physical properties of short chain alcohols?
- short-chain alcohols like methanol and ethanol have a low boiling point (ie lower than water) because they have weak intermolecular forces which are easily overcome.
- Alcohols have higher boiling points than their corresponding alkane (eg ethanol has a higher boiling point than ethane) because the –OH group has the effect of strengthening the intermolecular forces.
- short chain alcohols are very soluble in water because of the effect of the –OH group that is strongly attracted to water molecules.
37
What are the physical properties of long chain alcohols?
- higher boiling points than the short chain molecules
| - less soluble than the short chain because they behave more like alkanes and float on the surface
38
Why are alcohols good fuels?
Alcohols are good fuels because of the presence of the hydrocarbon chain. They burn in a good air supply to produce carbon dioxide and water.
39
How is fermentation used to make ethanol?
Through respiration of yeast:
Sugars are used by yeast as a source of energy for anaerobic respiration. Ethanol and carbon dioxide are the products:
glucose → ethanol + carbon dioxide
40
Why is fermentation limiting on the concentration of ethanol you can produce?
If the concentration of ethanol exceeds a certain level, it will start to kill the yeast. This means that there is a limit to the concentration of ethanol that can be achieved through fermentation.
41
How can the concentration of ethanol made through fermentation be increased?
the concentration of the ethanol can be further increased by distillation, which is how spirits like whiskey and brandy are made.
42
How can biotechnology be used to make ethanol?
Genetically-modified E. coli bacteria can be used to convert waste biomass from a range of sources into useful ethanol. The biomass might have come from plant matter such as maize stalks or wood waste.
43
How does synthesis of ethanol work?
Ethanol can be made using crude oil as a raw material:
1) Crude oil is processed by fractional distillation.
2 )Alkanes (such as ethane) are ‘cracked’ to produce alkenes - including ethene (C2H4).
3) Ethene is reacted with steam at high temperatures and in the presence of a phosphoric acid catalyst.
Any unreacted ethene and steam are recycled back into the process so that they are not wasted.
44
What are advantages of synthesis of ethanol over fermentation?
- Far higher yield
| - Once equipment is bought, can be made cheaply so good for large scale manufacturing
45
What are the advantages of fermentation over ethanol synthesis?
- Can be made using simple technology that is isn't expensive
- likely to be carbon neutral. This is because the amount of carbon dioxide that is produced when the ethanol is burned is the same as the amount that was absorbed by photosynthesis when the plants that have been fermented were growing.
46
What are the disadvantages of fermentation?
- only low concentrations can be made
| - expensive to make large quantities
47
What are the disadvantages of ethanol synthesis?
- requires very expensive equipment
| - not sustainable because it relies on oil - which is a fossil fuel.
48
What is produced when alcohols react with sodium?
a salt an hydrogen gas
For example:
ethanol + sodium → sodium ethoxide + hydrogen
49
What are the properties of ceramics?
ceramics are a range of durable compounds that change very little when heated.
- unreactive
- hard
- brittle
- poor electrical and thermal conductors
- high melting points
- Giant structure (ionic or covalent) with strong bonds
50
What is a polymer?
A large chain molecule made from lots of small monomers with a high average relative formula mass.
51
What is polymerisation?
The process in which monomers join together in a reaction. They are joined by covalent bonds.
52
What is addition polymerisation?
The way monomers join together. They do this by the double carbon bond splitting allowing two more connections in which they can attach to the polymer. Addition polymerisation is usually done by alkenes like ethene or propene)
53
What is the polymer general formula?
Cn H2n
54
How do you write the short hand formula for a polymer?
Write a section (one carbon-carbon bond) in brackets with an n after It. e.g (c-c)n (this is missing out the hydrogens)
55
How do you draw a monomer?
similar to the short hand formula but with a double c=c bond and an n in front of the monomer.
56
What are naturally occurring polymers?
DNA, starch and protein
57
How do you draw a endothermic reaction on a reaction profile graph?
Start with the reactants having higher amount of energy then draw a 'hump' ending with the products being lower than the reactants.
58
How do you represent activation energy on a reaction profile?
As a 'hump'/increase in energy
59
Does Bond breaking require energy or release energy?
Requires energy to break bonds
60
Does bond making require energy or release energy?
Releases energy when bonds are made
61
What does an exothermic reaction mean in terms of bond breaking/making?
More bonds are made than broken hence releasing more energy than used up making it exothermic.
62
What is a reaction profile?
An energy-time graph showing the energy levels of a reaction decreasing (endothermic) or increasing (exothermic) in energy
63
If an exothermic reaction happens in a solution, what happens to the temperature of a solution?
It will increase as energy is released
64
What is a reversible reaction?
A reaction in which the products can reform the reactants
65
What is a dynamic equilibrium?
When in a reversible reaction, the forward reaction (reactants to products) occur at the same time as the backwards reaction (products to reactants). This is only possible in a closed system
i.e. two opposite changes happen at the same time but there is no overall change in the system.
66
In a dynamic equilibrium, what is the rate of the forward reaction equal to?
The rate of the backwards reaction.
67
What is a closed system?
It is an environment like a sealed container where things like gases cant escape.
68
What happens to the dynamic equilibrium if system is change?
The dynamic equilibrium will shift in position to minimise the change made.
69
What are the common changes to happen to a dynamic equilibrium?
- temperature
- pressure
- concentration
70
What happens to the dynamic equilibrium if the temperature is increased?
If the temperature is increased, then the equilibrium will shift to the left (the endothermic direction), to remove the extra heat added. This means the rate of the endothermic reaction will increase.
71
What happens to the dynamic equilibrium if the temperate is decreased?
The equilibrium will shift to the right (the exothermic direction), to increase the thermal energy taken in. This means the rate of the exothermic reaction will increase.
72
What happens to the dynamic equilibrium if the pressure is increased?
The equilibrium will shift to the right, in the direction of the fewest molecules. Increasing the rate of reaction
73
What happens to the dynamic equilibrium if the pressure is decreased?
If the pressure is reduced, the equilibrium will shift towards the left, resulting in more reactants and in the direction of the most molecules.
74
What happens to the dynamic equilibrium if the concentration increases?
The equilibrium will shift to decrease the concentration of the substance by increasing the forward reaction.
75
What is the Haber process?
The process by which ammonia is mad from reacting hydrogen and nitrogen.
76
How do you increase the yield of ammonia in the Haber process?
Increase the rate of the forwards reaction as it is reversible by:
- not having a too high temperature (high enough for the reactants to react)
- having a high pressure
- using a catalyst (iron)
77
What are the differences between the process of making ammonium fertiliser in a lab and a factory?
LAB
-uses ammonia solution and dilute sulphuric acid
-only involves a few stages with low yield
FACTORY
-uses sulphur, air and water
-many stages with high yield
78
Why is the industrial production of a substance continuous?
Because a lot is made
79
How do chemical fuel cells work?
IN a solution:
Electrons pass from one metal through a wire to a more reactive metal. The ions then pass through the solution to the other metal to complete the circuit.
80
How does a hydrogen oxygen fuel cell work?
Hydrogen comes in and loses electrons at the platinum electrode (2H2 -> 4H+4e-) The electrons move along the electrode to the motor, generating electricity and then come back to the right electrode where the hydrogen collects the electrons, react with oxygen to produce water.
81
How do you do a titration calculation?
1) You write out the equation of the reaction and read the question to find out which substance you are trying to work out the concentration of e.g
NaOH + HCl -> NaCL + H20
2) replace the names in the equation with the known volumes.
25cm3 + 24.88 cm3 -. NaCL + H20
3) Use the known concentration in equation moles= concentration x (volume/1000)
0.1 x 25/1000 = 2.5 x 10-3 moles of NaOH
4) Use the molar ratio
because there is no numbers in the equation it is 1:1 but if it was 2HCL then would be 1:2
5) Use the equation concentration = moles/(vol/100)
82
How do you do a concentration (key points)
1) Write out the equation
2) use equation moles = concentration x vol/1000
3) Write molar ratio
4) use equation concentration = moles/(vol/1000)
83
What is the equation that allows you to find concentration from moles and volume?
Concentration (mol dm-3) = moles/(volumes/1000)
or
concentration (g/dm-3) = mass/(volume/1000)
84
What does it mean when a compound is saturated in terms of bonds?
Contains a carbon -> carbon bond with only single bonds
85
What is a hydro carbon in terms of bonds?
Contains a carbon carbon bond with double or triple bonds
86
What is the homologous series?
compounds with similar structures and properties that can be given a genera formula. Alkanes are a homologous series of saturated hydrocarbons with the general formula C(n) H(2n+2)
n=no. of atoms
87
What are the uses of alkanes?
- fuels for planes, ships, cars
- heating
- power stations
88
What are the chemical properties of alkanes?
The alkanes undergo complete combustion, when they react completely with oxygen, carbon dioxide and water vapour is formed.
89
What is crude oil?
a mixture of different length hydrocarbons
90
Why is cracking necessary in the fuel industry?
To make more sort chain hydrocarbons which are better for burning and are more valuable.
91
What does cracking involve?
splitting long chain molecules into short chain molecules by passing them through a catalyst.
92
What is the difference between an alkane and alkene?
An alkene is unsaturated whereas an alkanes is staurated
93
What is the EMMA method?
```
Used for titration calculations
Equation
Moles
Molar ratio
Answer
```
