C1 Flashcards
1
Q
Using the periodic table how can you work out the number of shells an element has?
A
The number of rows down the element is = the number of shells
2
Q
Using the periodic table how can you work out the number of electrons an element has in it’s outer shell?
A
The number of electrons in the outer shell = the column number
3
Q
Where is a proton in an atom? How much does it weigh? What is their charge?
How do you calculate the number of protons in an atom?
A
In the nucleus.
1
+1
The atomic number
4
Q
Where is a neutron in an atom?
How much does it weigh?
What is their charge?
How do you calculate the number of neutrons in an atom?
A
In the nucleus
1
0
The mass number minus the atomic number
5
Q
What is the charge of a nucleus?
A
Positive
6
Q
Where is an electron in an atom?
How much does it weigh?
What is their charge?
A
Orbits the nucleus, occupies shells
Almost 0
-1
7
Q
What charge does an atom have? Why?
A
Neutral. The electrons cancel out the positive charge
8
Q
How do you make an Ion?
A
An Ion is a charged particle that has had an electron added or removed
9
Q
What is a compound?
A
A substance of two + elements that are chemically bonded. Once bonded it becomes difficult to separate the two original elements
10
Q
Name two different types of compounds and which types of elements they occur between?
A
Ionic - a metal and a non-metal
Covalent - a non-metal and a non-metal
11
Q
In an Ionic bond what are the charges of the parts?
A
The metal ion loses a electron to become positive. The non metal gains an electron and becomes negative. Opposites attract.
12
Q
Balance this equation…
H(2)SO(4) + NaOH –> Na(2)SO(4) + H(2)O
A
H(2)SO(4) + 2NaOH –> Na(2)SO(4) + 2H(2)O
13
Q
What is the chemical symbol for limestone?
A
CaCO(3) Also known as calcium carbonate.
14
Q
What happens to limestone when it’s heated?
Whats the equation?
A
It thermally decomposes and forms calcium oxide, also known as quick lime & carbon dioxide
CaCO(3)[s] –> CaO[s] +CO(2)[g]
15
Q
What is CaO?
A
calcium oxide/quick lime
16
Q
Calcium oxide reacts with water to form…
What is the equation?
A
Calcium hydroxide/slaked lime
CaO + H(2)O –> Ca(OH)(2)
17
Q
What is Ca(OH)(2)?
A
Calcium hydroxide/slaked lime
18
Q
What is carbon hydroxide used for?
A
It’s an alkali that is used to neturalise acidic soil.
19
Q
How can you test for Carbon dioxide?
A
Bubble the gas through limestone which will turn cloudy if there’s carbon dioxide present.
20
Q
What happens when you add Carbon Dioxide to Carbon hydroxide?
A
It forms calcium carbonate (limestone) and water.
21
Q
A metal carbonate reacts with acid to make…
A
…A salt, carbon dioxide and water
22
Q
What is Thermal decomposition?
A
When a substance is heated and chemically changes into 2+ substances
23
Q
How do you make cement?
A
Crushed limestone + powered clay heated in a kiln at 1450°c + calcium sulfate
24
Q
What is Mortar made of?
What is Concrete made of?
A
Mortar; Cement, sand + water
Concrete; Cement, aggregate (gravel + water)
25
Name the advantages (5) of using Concrete when building...
1) Concrete is strong when squashed.
2) You can custom mould it when wet
3) It's cheap and quick
4) It won't rot (like wood) or corrode (like metal)
5) It's fire resistant
1) It is Ugly
2) low tensile strength; cracks if bent or stretched
26
Name four disadvantages of quarries?
1) Quarries are unsightly
2) Cause noise pollution (explosives)
3) Quarries destroy habitats
4) Exhaust fumes from the Lorries contribute to the Green house effect
27
Three advantages of quarries?
1) Creates jobs for people bringing money into the economy
2) It provides building materials
3) After the quarry is used, they usually are made into nature reserves
28
What are the advantages of using limestone as a building material?
Cheap and hard wearing but i eroded by acid rain
29
Name the disadvantages of cement...
Making process creates lots of dust which causes breathing problems. The energy used to produce it usually comes from fossil fuels; pollution
30
You can make concrete stronger by...
You can make concrete stronger by reinforcing it with steel.
31
What are the uses of Limestone?
1) A building material.
2) Powdered limestone is used neutralize acidic soil (slower than calcium hydroxide)
3) When manufacturing cement, glass & iron
4) To produce calcium oxide (quick lime)
32
What is an ore?
A rock that contains metal-compound
33
What is aluminium ore?
Bauxite
34
Why would you need to chemical reactions to extract metals?
Unreactive metals like gold are found in the Earth as the metal itself but most metals are found as compounds so need a chemical reaction to extract the metal.
35
What can be used to extract a metal less reactive than carbon?
Metals less reactive than carbon can be extracted from their oxides by reduction with carbon. Carbon can only remove oxygen from metals which are less reactive than itself.
36
What happens in reduction?
When a ore is reduced Oxygen is removed, this happens in a blast furnace (smelting).
37
1) When would you use electrolysis?
| 2) What are 2 examples of metals that are extracted with electrolysis?
1) For a metal more reactive than carbon.
| 2) aluminium and copper
38
1) What is electrolysis?
| 2) What is an electrolyte?
1) It is the breaking down of substances using electricity
2) Either metal salt solution made from the ore or a molten metal oxide. An electrolye contains free ions which conduct the electricity and are key.
39
What happens in electrolysis?
1) A negative electrode (aka. cathode) and a positive electrode (aka. anode) are placed in a solution and a current is passed through.
2) The solution is either an ionic molten metal oxide or an ionic metal salt solution, this means it is made up of a negatively charged part and a positively charged part.
3) The current causes the electrons to leave the anode and go to the cathode (This is the end of the circuit).
4) The positive metal ions are attracted to the cathode. At the cathode an electron is given to the ion causing it to become a pure metal atom. (if something gains an electron it becomes negative-this cancels the positivity of the metal ion)
5) The negative non metal ions are attracted to the anode where electrons are pulled off by the anode.
40
1) What would be the 1/2 equation for copper in a copper chloride solution at the cathode?
2) anode?
1) Cu2+ + 2e- --> Cu
| 2) 2Cl- --> Cl2+ + 2e-
41
Copper extracted by reduction with carbon in a furnace (smelting) is impure.
How do you purify it? Why?
Electrolysis, pure copper is a better conductor
42
How does displacement work?
If you put a reactive metal into a solution of a dissolved metal the reactive metal will replace the less reactive metal in the compound, this is because the more reactive metal bonds more strongly to the non metal compounds displacing the less reactive metal .
43
How would you use displacement to extract copper?
| Positives? Negatives?
```
Scrap iron (cheap) is put in a copper sulfate solution, the iron is more reactive so displaces the less reactive copper from the solution. An equation for this particular displacement will go cooper sulfate + iron --> iron sulfate + copper.
The metal must be MORE reactive than the metal (copper) in the solution
```
+ cheap; scrap metal
- Takes a long time
44
What does the short supply of copper ores mean?
There may be shortages in the future because of the demand.
| We need to recycle copper
45
What Is bioleaching?
| Positives? Negatives?
Bacteria get energy from the bond between copper and copper sulfide, this separates the metal and ore, produce a leachate solution containing copper which can be filtered out.
+ Easy
+ No emissions
-slow (compared to smelting)
46
What is phytomining?
| Positives? Negatives?
Planting on low grade copper ores, plants absorb copper but can't use/get rid of copper so it builds up in leaves. The plants can then be harvest and burned creating a copper rich ash
+ cost effecive
- Air pollution
- Takes a long time
47
Electrolysis;
| Positives? Negatives?
+ Fast
| - Uses lots of electricity; expensive
48
Name positives of metal extraction.
| Name negatives of metal extraction.
+ Useful products metal)
+ Provides people with jobs
+ Brings money into the area (improve transport and other services)
- Bad for the environment
- Scars landscape
- Loss of habitats
- Mine shafts are danger (fall through)
- Uses lots of energy (comes from burning fossil fuels)
49
Why should we recycle metals?
Recycling metals uses a small fraction of the energy need to mine and extract them;
Less fossils fuels are used (which are bad for the environment)
It's cheaper as energy is expensive.
Conserves the finite resources of metal.
Cuts down on landfill (takes up space & pollutes surroundings)
50
1) Name 2 properties of metals.
| 2) What are metals useful for?
```
#1 Strong (can still be hammered/bent into shapes)
#2 Good conductors of heat and electricity
```
2) Structural materials or for making things that must allow heat or electricity to pass through them easily.
51
What is metal fatigue?
When stresses/strains are placed on metals they become 'tired' and break
52
What are the properties of copper?
| Uses?
```
#1 Good conductor of electricity
#2 Hard and strong
#3 Malleable
#4 Doesn't react with water
```
Plumbing, copper pans, moulds, coins and electricity
53
What are the properties of aluminium?`
Why is it expensive?
Uses
```
#1 Corrosion resistant
#2 Strong
#2 Low density
It is expensive because it uses lots of electricity (electrolysis)
Aeroplanes
```
54
What are the properties of titanium?
| Uses?
```
#1 Low density
#2 Very strong
#3 Corrosion resistant
```
Replacement hips
55
What is cast iron?
Impure iron straight from the blast furnace, it is very brittle.
56
Why are pure metals malleable?
The atoms sit in a regular arrangements so easily slide over each other.
57
What is steel?
A compound of iron,carbon (sometimes other metals as well)
58
Low carbon steel;
What percentage is carbon?
What are it's properties
What are it's uses?
DOUBLE CHECK
1) 0.1%
2) Easily shaped
3) car bodies, food cans
59
High carbon steel;
What percentage is carbon?
What are it's properties
What are it's uses?
DOUBLE CHECK
1) 1.5 %
2) Very hard, inflexible
3) Construction, bridges, cutting tools
60
Stainless steel;
What is added?
What are it's properties
What are it's uses?
1) chromium (sometimes nickel)
2) Corrosion resistant
3) Cutlery, surgical instruments, kitchen sinks
61
How do you calculate density?
Density = mass / volume
62
1) What is Bronze made from?
| 2) What is it used for?
1) Bronze = Copper + Tin
| 2) Medals and statues
63
1) What is Curonickel made from?
| 2) What is it used for?
1) Curonickel = Copper + Nickel
| 2) 'silver' cons (5p/10p)
64
Why would you use a gold alloy?
Pure gold is too soft, other metals are added to harden it
65
Why would you use an aluminium alloy?
Aluminium has a low density so is alloyed to make it stronger
66
What is Crude oil?
A mixture of hydrocarbons.
It's a fossil fuel so it formed from the remains of plants and animals. It's non renewable as the conditions required to make it (warm oceans) don't exist anymore
67
What is a hydrocarbon?
A hydrocarbon is made from hydrogen and carbon only.
68
Why do hydrocarbons keep there original properties?
Unlike a compound the parts in a mixture aren't chemically bonded together. This means the parts can be seperated out by physical methods
69
What is a mixture?
Two or more elements / compounds that aren't chemically bonded together
70
How does fractional distillation work?
1) The crude oil is heated at the bottom of the column
There is a temperature gradient in the fractionating column so it’s a lower temperature at the top and a higher temperature at the bottom.
2) The hydrocarbons with the highest boiling points don't vaporise, remaining as liquids and are tapped out of the bottom of the column.
3) But most of the hydrocarbons form gases and rise up the fractioning column.
4) The gases then cool as they rise up the fractionating column, because different hydrocarbon molecules aren’t chemically bonded they retain their original properties like condensing points. For example smaller hydrocarbons condense at low temperatures whilst larger hydrocarbons condense at higher temperatures.
As the vaporised gas then rises it condenses at different points and is tapped off accordingly (Hydrocarbons with low boiling points condense near the top of the fractionating column in the lower temperatures, whilst hydrocarbons with high boiling points condense near the bottom of the fractionating column)
5) Some of the hydrocarbons remain as gases and rise out of the top of the fractionating column.
71
As you go up the fractionating column, what trends are there in the properties of hydrocarbons have?
```
Lower boiling points
Lower viscosity (they flow more easily)
Higher flammability (they ignite more easily)
```
72
Name 4 uses of Crude oil...
```
#1 Transport (petrol),
#2 Electricity generation
#3 as a raw material (e.g. in plastics)
#4 Heating
```
73
How has technology helped use mine oil?
It is now possible to extract oil that was once too expensive or difficult
74
What are alternates to fossil fuels?
Renewable energy sources like tidal, wind and solar power
75
What things might we have to adapt if crude oil runs out? And why is this a problem?
Alternative fuel sources and the methods/machines to use them (different car engines)
It will take time to do so.
76
What is one environmental risk of using crude oil?
Oil spills, it poisons birds and other sea life
77
What is produced when fossil fuels are burnt with oxygen?
| Hydrogen?
oxide of elements; hydrocarbons + oxygen --> carbon dioxide + water vapour
hydroxide
78
Carbon dioxide and water are produced during combustion when fossil fuels are burnt. What does Carbon dioxide cause?
Carbon dioxide contributes to the green house effect, which is causing global warming. global warming is a type of climate change and could cause severe floods
79
What is formed is incomplete combustion occurs?
Particulates (soot) and carbon monoxide
80
What is the effect of carbon monoxide?
It is toxic to people
81
What do particulates cause?
Smog, this can cause asthma attacks.
| They also cause global dimming
82
What do sulphur dioxide and oxides of nitrogen cause?
Acid rain
83
Name a source of;
1) Carbon monoxide
2) Carbon dioxide
3) Particulates
4) Sulphur dioxide
5) Oxides of nitrogen
1) Incomplete combustion
2) Humans
3) Incomplete combustion
4) Exhaust fumes
5) Car engines
84
How can you reduce acid rain?
By reducing sulfur dioxide emmisions;
1) You can remove sulfur from fuels before they’re burnt; but it's expensive and uses up more energy (producing CO2)
2) Power stations have acid gas scrubbers to take gases out before being released
3) Petrol and Diesel are being replaced by low sulfur versions
85
What is Global dimming?
Particles of soot and ash produced by fossil fuels are reflecting sunlight into spaces/producing more clouds. The level of sunlight reaching the earth today is 25% less than 50 years ago
86
What is the formula of alkanes?
| What is the acronym to remember the order?
CnH2n+2
| MEPB (My Elephant picks bananas)
87
What bonds do Alkanes form?
| Draw a diagram for Methane...
```
Single bonds
H
I
H - C - H
I
H
```
88
1) What is the chemical formula for Methane?
2) What is the chemical formula for Ethane?
3) What is the chemical formula for Propane?
1) CH4 (work out by CnH2n+2: C1; H2*1+2)
2) C2H6 (work out by CnH2n+2: C2; H2*2+2)
3) C3H8 (work out by CnH2n+2: C3; H3*2+2)
89
What colour does Bromine water turn if passed through an alkane?
It will stay orange
90
What is meant by saying alkanes are saturated?
They have formed bonds with as many molecules as they can.
91
What are 3 alternate fuels instead of fossil fuels?
Ethanol
Biodiesel
Hydrogen gas
92
What is biodiesel?
| Pros and cons?
Biodiesel is a type of biofuel. Made from processed vegetable oils it can be mixed with ordinary diesel and used in cars.
+ carbon neutral,
+ produces less sulphur dioxide and particulates
+ engines don't need to be converted
- can't make enough to replace diesel
- expensive
- People will grow crops like rapeseed and soybean to make the oil instead of food
- Deforestation to make space for crops
93
What are the uses of ethanol?
Hand sanitizer, solvent, alcoholic drinks, perfumes. It can be used as a cheap fuel to power cars in countries that don't have oil reserves.
94
What methods can you use to make ETHANOL
It can either be produced by
1) The hydration of Ethene... or....
2) The fermentation of plants (this method is used for beer/wine).
95
How do you produce Ethanol by fermentation?
Sugar is converted into ethanol using yeast.
Yeast contains a natural catalyst (enzymes) that turn glucose into ethanol
Sugar --> carbon dioxide + ethanol
It is then filtered to remove yeast, then distilled to concentrate the ethanol.
96
What is the hydration of Ethene?
If you hydrate Ethene with steam (H2O) in the presence of a catalyst you make ethanol.
C2H4 + H20 --> C2H5OH
97
Pros and cons of the hydration of Ethene?
+ Fast
+ Pure product
+ Cheap (at the moment- but crude oils will run out so the price will go up)
- Non-renewable (uses crude oil)
98
What are the 5 advantages of using fermentation instead of hydration to produce Ethanol?
+ Fermentation needs a lower temperature
+ Fermentation needs simpler equipment.
+ The raw material (sugar) is renewable while ethene (a crude oil) will run out
+ Sugar is widely available; major crop
+ Carbon neutral; CO2 taken in by plants and released when the fuel is burnt
(No fossil fuels used in making)
99
What are the 3 disadvantages of using fermentation instead of hydration to produce Ethanol?
- The ethanol produced by fermentation isn't very concentrated and has to be distilled
- Hydrating ethene is cheaper
- People will grow crops for ethanol instead of food; need to import food
100
Pros and cons of ethanol as fuel?
+ Renewable
+ Carbon neutral
- Car engines have to be converted to use ethanol
101
How it hydrogen gas made?
| Pros and cons?
```
The electrolysis of water.
+ Water isn't unlikely to run out
+ Clean process; only produces water
- Expensive (need to power electricity)
- Hydrogen's hard to store (explosive)
```
102
Why do people crack long chain hydrocarbons? What is this process called?
To form more useful substances like petrol, ethene and paraffin from not so useful hydrocarbons like bitumen. This is called cracking.
103
1) What type of reaction is cracking?
| 2) What are the products of cracking?
1) Thermal reaction
| 2) Alkanes and alkenes
104
What happens during cracking;
Heat long chain molecules into a gas
Pass the gas over a powdered catalyst (aluminium oxide) at 400oc – 700oc
The long chain molecules ‘crack’ on the surface of the specks of catalyst
Most products of cracking are alkanes and alkenes
105
1) What bonds do Alkenes have?
| 2) Why are Alkenes described as unsaturated?
1) Double C=C bonds
| 2) They can make more bonds by breaking the double bond
106
What is the formula of alkenes?
| What are the first two alkenes?
CnH₂n
Ethene C2H4
Propene C3H6
107
How can you test for alkenes?
Add the substance to bromine water; it will turn colourless if there are alkenes present. this is because the double bond has opened up and formed bonds with the bromine
108
1) Draw Ethene molecule...
| 2) Draw a Ethane molecule...
```
1) H H
C=C
H H
In alkenes some hydrogen will be diagonal. There will also be a double bond
2) H
I
H - C - H
I
H
In alkanes hydrogen will be above/below/to the side
```
109
What is polymerization?
The joining of monomers (small alkene molecules) to form polymers (joined up monomers)
110
How would you draw out a polymer molecule?
H H H H H H
-(-C-C-C-C-C-C-)-
H H H H H H
This is just the layout, Carbon molecules with hydrogen on top/below and a long line bisecting a bracket at either end of the carbon molecule line
111
What determines the physical properties of a polymer?
The temperature and pressure during polymerisation.
Poly(ethene) at 200^ and 2000 atmospheres is flexible and low density
Poly(ethene) at 60^ and 4 atmospheres pressure with a catalyst is rigid and dense
112
How does Low density Poly(ethene) and high density Poly(ethene) structurally differ?
High denisity Poly(ethene)has no branches between polymers whilst Low density Poly(ethene) has lots of branches
113
Name 3 smart polymers and their uses...
Polymer hydrogel --> nappies/wound dressings
Memory foam; soft when warm; beds
Polyethene; shrinkwrap
114
What will happen to the price of polymers?
It will rise as crude oil resources are used up
115
What are the advantages and disadvantages of landfill?
+ Cheap
+ Quick
- Pollution of water (groundwater)
- Loss of habitats
116
What are the advantages and disadvantages of incineration (burning them-often used to generate electricity simultaneously) ?
+ Creates electricity
- Smells; toxic fumes
- Ash from the polymer still goes to landfill
117
Polymers are recyclable;
| What are the advantages and disadvantages of recycling?
+ Creates jobs (e.g. at recycling plant)
+ Better for the environment
+ Sustains the resource
- Recycling uses energy (e.g. lorries to transport)
118
How do you extract oils from a plant?
Either pressing, solvents, centrifuge or distillation.
119
How would you traditionally extract oil from olives using Pressing?
1) Harvest the olives and crush into a paste.
2) Spread the paste onto metal discs and place under pressure (press)
3) Collect the liquid
120
What is centrifuge?
Separation of oil by spinning the crushed plant very fast
121
How do you distill lavender?
| Why would you use distillation?
Crush the lavender plants, mix in water and heat in distillation flask. The oil evaporates along with the water, the vapor is condensed and naturally separates.
Distillation refines oil, removes water, solvents and impurities
122
Positives of eating plant oils? And negatives?
They are high in energy, 3800j per 100g.
Oil also contains nutrients like vitamin E (antioxidant-protects cell membranes from damage).
Contains oleocanthal; anti inflammatory
But if you eat lots of oil rich food and don't exercise you may put on weight; heart disease
123
Why do people cook with oil instead of water?
Oil has a higher boiling point than water; cook food at higher temperature, adds flavour
124
What type of bonds do oils and fats have?
Long chain molecules with lots of carbon.
125
1) Why are saturated fats/oils not very healthy?
| 2) How could you tell if a oil/fat was saturated or unsaturated?
1) They increase your blood cholesterol; heart disease
| 2) Add it to bromine water; colourless if unsaturated
126
What is the difference between a Monounsaturated fat and a Polyunsaturated fat?
A monounsaturated fat only has one C=C bond whilst a polyunsaturated fats has 2+ C=C bonds
127
1) What is hydrogenation?
| 2) Why would you want a hydrogenated oil instead of a unsaturated oil?
1) Unsaturated oils can be hardened by hydrogenation; oil is reacted with hydrogen gas at 60oc over nickel catalyst. Hydrogen reacts with double bonded carbons and opens out the double bonds.
2) Hydrogenated oils have higher melting points so are solid at room temperature.
128
1) Why is margarine partially only partially hydrogenated?
2) Why might you use hydrogenated margarine?
3) Why shouldn't use eat too much hydrogenated vegetable oils?
1) If all the bonds were single the margarine would be too hard.
2) Partially hydrogenated margarine is easy to spread. Margarine is cheaper than butter and keep longer
3) They contain transfats which are very bad
129
What is an emulsion?
| What are emulsifiers?
A mixture of oil and water
Emulsifiers are molecules, one end is hydrophilic (attracts water molecules) and one end is hydrophobic (repels water-attracts oil molecules)
130
What are the advantages and disadvantages of emulsifiers?
+ Stop separating (oil droplet coated by emulsifier which has the hydrophilic end sticking out)
+ Longer shelf life
+ Low fat food
- Allergies (egg-used)
131
What did people believe caused mountains before Wegener?
Mountains formed because the Earth was cooling down, and in doing so contracted and wrinkled
132
What was Alfred Wegener's theory?
| Why did he think this?
Continental drift; there had once just been a giant super continent (pangaea) which had broken into pieces and was still drifting apart.
He noticed fossils found in South Africa were the same as in West Africa, and the rock was the same as well. Also they looked like they fitted together
133
Why did no-one believe Wegener?
```
He was young
He wasn't a geologist
He couldn't explain how it happened
Not enough evidence
(His calculations were incorrect)
```
134
```
Describe the...
Crust
Mantle
Inner core
Outer core
```
Crust; thin 5km-50km (surrounded by atmosphere)
Mantle; molten (radioactive decay-heat), flows slowly in a convection current
Inner core; iron and nickel
Outer core; iron and nickel
135
Define continental drift...
The crust of the earth is broken into pieces called the tectonic plates. The plates move (a rate of a few cm/year) because of convection currents in the Earth’s mantle, formed by heat produced in the natural decay of radioactive elements.
136
What geographical feature occurs at the boundaries of the plates?
Volcano's
137
What is an earthquakes?
When two tectonic plates suddenly move
138
Scientists can look for strain in rocks, bulges in the ground where and mini-earthquakes near volcano but can't always be right. Why?
Scientists cannot monitor what's happening in the mantle. Not all small earthquakes indicate an eruption, some may be false alarms
139
```
Describe the...
Crust...
Mantle...
Inner core...
Outer core...
```
Crust; thin 5km-50km (surrounded by atmosphere)
Mantle; molten (radioactive decay-heat), flows slowly in a convection current
Inner core; iron and nickel
Outer core; iron and nickel
140
What was the early earth like? What gases were present and where did they come from?
The surface of the earth was molten. Volcanic activity produced lots of CO2 and some water vapour, methane and ammonia. There was (virtually) no oxygen
141
How did oceans form?
| What happened to the CO" in the atmosphere?
The water vapour condensed
Lots of the early CO2 dissolved into the oceans, but some was absorbed by the green plants and algae. Plant produced oxygen in photosynthesis.
142
What did carbonates and and fossil fuels form from?
The buried remains of the early plants, algae and the shells/skeletons of early sea animals.
143
What allowed the evolution of complex organisms?
The ozone layer, it blocked harmful rays from the sun
144
What is earth's atmosphere composed of today?
Oxygen-21%
Nitrogen-78%
Sulphur dioxide & Carbon monoxide & Carbon dioxide & Argon-1%
145
1) Why are carbon dioxide levels rising?
| 2) What group might this affect (not people)
1) Lots of fossil fuels are being burnt and deforestation.
| 2) Sea life; as the ocean absorb more CO2 it becomes more acidic
146
What did Miller and Urey attempt to prove?
The primordial soup theory; the earth's atmosphere was rich in nitrogen, hydrogen, ammonia and methane, lightning caused a chemical reaction producing amino acids from which life formed.
147
How can you get just pure oxygen (filtering the air)
Lower the temperature to -200^, remove frozen water, remove frozen carbon dioxide (dry ice).
Warm it to 190^ and remove the evaporated nitrogen (oxygen & argon remain as liquids)
Carry on heating it until the argon evaporates.
Hey presto!
148
What does more volatile mean?
Turns into a gas at a lower temperature
149
Where does crude oil come from?
Crude oil is derived from an ancient biomass found in rocks
150
You can crack long chain hydrocarbons by passing them over a powdered aluminium oxide catalyst, but what is an alternative method?
Mixing the long chain molecule with steam at a high temperature so that a thermal decomposition reaction can then occur.
