C1 Flashcards
1
Q
what does the nucleus contain?
A
protons and neutrons
2
Q
element
A
substance containing only one type of atom
3
Q
molecule
A
2 or more atoms bonded together
4
Q
compound
A
Acompoundis a substance formed when two or morechemicalelements are chemically bonded together.
5
Q
mixture
A
2 or more atoms/compounds not chemically bomded
6
Q
where is the lowest energy level?
A
the shell closest to the nucleus
7
Q
what is ionic bonding?
A
Metal + Non-metal
metal loads electrons to form positive ions, non-metal gains electrons to form negative ions
opposite charges attract
8
Q
what is a covalent bond?
A
non-metal + non-metal
each atom shares electrons with another ago! to get a full outer shell.
they can form small molecules of giant lattices
9
Q
describe the limestone cycle
A
CaCO3 -> CaO -> Ca(OH)2(s) -> Ca(OH)2(aq)
10
Q
what is produced when limestone thermally decomposes?
A
Carbon dioxide and Calcium Oxide
11
Q
what is needed to turn CaO into Ca(OH)2??
A
water
12
Q
what is needed to turn calcium hydroxide solution into calcium carbonate??
A
carbon dioxide
13
Q
what is limestone used for?
A
cement, mortar, concrete, Glass, buildings
14
Q
what are the advantages of quarrying?
A
- provides jobs
- crater could be used for leisure activities
- money made from products
- can be used as a nature reserve or landfill afterwards
15
Q
what are the disadvantages of quarrying?
A
- noise pollution
- huge crater can be seen from miles away
- blasting may scare off wildlife
- lorries are not eco-friendly + wear away at verges
- jobs are not permanent
- quarry costs a lot to set up
16
Q
limestone is good because:
A
- limestone is widely available and cheaper than other rock
- hard wearing but still attractive
- doesn’t rot or corrode
17
Q
metal ore
A
a rock which contains brought metal to make it economically viable to extract the metal from it
18
Q
describe reduction with carbon
A
when an ore is reduced the oxygen is removed
the position of the metal in the reactivity series determines whether it can be extracted by reduction ( must be below carbon)
done in a blast furnace
19
Q
what is electrolysis
A
the breaking down of a substance using electricity
metals more reactive than carbon have to be extracted with electrolysis of molten compound
20
Q
describe the process of electrolysis
A
The electrolyte is the liquid which conducts the electricity and are often metal salt solutions or molten metal oxides. The electrolyte has free ions which conduct electricity.
electrons are pulled off the metal at the anode causing the metal to go into the solution as ions, the ions are attracted to the cathode where they gain electrons and turn back into metal atoms. impurities are dropped at the anode as sludge.
21
Q
What is the overall charge on an atom?
A
neutral (0)
22
Q
What is the charge of a proton?
A
+1
23
Q
What is the charge of a neutron?
A
0
24
Q
What is the charge of a electron?
A
-1
25
What is the relative mass of a proton?
1
26
What is the relative mass of a neutron?
1
27
What is the relative mass of a electron?
negligible (1/1840)
28
What does the atomic number tell you on the periodic table?
how many protons it has (and also how many electrons)
29
What does the mass number tell you in the periodic table?
how many protons + neutrons
30
What is thermal decomposition?
breaking down a chemical using heat
31
What is calcium hydroxide used for?
neutralisation. it is an alkali.
| e. g. farmers might use it on fields to neutralise soil
32
how do you test for carbon dioxide?
bubble it through limewater, if it goes cloudy it is CO2
33
What is cement made from?
heated limestone and clay
34
What is concrete made from?
cement, sand and aggregate (rocks/stones)
35
what is mortar made from?
cement and sand
36
Why does gold stay shiney for a longer time than copper?
gold is less reactive
37
What is phytomining?
phytomining uses plants to absorb metal compounds and that the plants are burned to produce ash that contains the metal compounds
38
what is bioleaching?
bioleaching uses bacteria to produce leachate solutions that contain metal compounds.
39
why is it expensive to remove aluminium and titanium from their ores?
there are many stages in the processes and large amounts of energy are needed.
40
why is recycling metals a good idea?
- extracting them uses limited resources
| - it is expensive in terms of energy and effects on the environment to extract new ores
41
what is steel?
Steels are alloys since they are mixtures of iron with carbon. Some steels contain other metals.
42
What is an alloy?
a mixture of metals
43
Low carbon steel
has 0.1% carbon
Low-carbon steels are easily shaped
used for car bodies
44
why are gold, copper and aluminium often made into alloys?
Pure copper, gold, iron and aluminium are too soft for many uses and so are mixed with small amounts of similar metals to make them harder for everyday use.
45
what is copper useful for?
Copper has properties that make it useful for electrical wiring and plumbing. is a good conductor of electricity and heat
can be bent but is hard enough to be used to make pipes or tanks
does not react with water.
46
why are aluminium and titanium very useful?
Low density and resistance to corrosion make aluminium and titanium useful metals.
47
What is crude oil made from?
a mixture of hydrocarbons
48
Why do the hydrocarbons keep their original properties?
Because there are no chemical bond between different hydrocarbons
49
What are alkanes?
Saturated hydrocarbons with no double bonds. Each carbon has as many Hydrogen bonds as possible
50
What are alkanes?
Saturated hydrocarbons with no double bonds. Each carbon has as many Hydrogen bonds as possible
51
What does a short chain result in?
- less viscous
- more volatile
- more flammable
- lower boiling point
52
Why is crude oil bad for the environment?
- oil spills can poison birds and whales
| - burning them releases carbon dioxide, particulates, sulfur dioxide and even carbon monoxide
53
What are the positives of using ethanol as a fuel?
- its carbon netral
54
What are the negatives of using ethanol as a fuel?
- engines would need to be converted
55
What are the positives of using bio-diesel as a fuel?
- carbon neutral
56
What are the negatives of using bio-diesel as a fuel?
- expensive to make
| - can't make enough
57
What are the negatives of using hydrogen gas as a fuel?
- hard to store
| - needs an special expensive engine
58
What are the negatives of using hydrogen gas as a fuel?
- clean fuels (produces water)
59
What is cracking?
when long hydrocarbon chains (which are not efficient) are broken down into smaller chains
60
What is ethene?
Unsaturated hydrocarbons with double bonds. Each carbon does not have as many hydrogen bonds as i could have.
61
What is the general formula of ethene?
CnH2n
62
What is the method for cracking
- the hydrocarbon is heated to vapourise it.
- then it is passed over a catalyst and the long chain split apart into smaller molecules.
- it results in alkanes and alkenes being made
63
What conditions are needed for cracking?
- 700 degrees
| - aluminium oxide catalyst
64
What is fractional distillation?
When crude oil is separated into different chain lengths of hydrocarbon.
65
What are the uses of a short chain hydrocarbon?
- petrol (easy to store)
66
What are the uses of a long chain hydrocarbon?
covering roads and lubricating engine parts
67
How can ethanol be made?
- hydrating ethene
| - fermentation
68
What conditions are needed for hydrating ethene?
- high temperature
- high pressure
- catalyst
69
What conditions are needed for fermentation?
- room temperature
- normal pressure
- yeast
70
Advantages of hydrating ethene
- Fast reaction
- Produces pure ethanol
- Continuous process, no shut down time between bathces
71
Advantages of fermentation
- renewable, uses waste materials
| - less extreme conditions, costs less
72
Disadvantages of hydrating ethene
- not renewable
| - lots of energy needed for the right conditions
73
Disadvantages of fermentation
- doesn't make pure ethanol
- slow process
- large volumes needed to make a small amount product
74
What is polymerisation?
openignall the double bonds on alkene monors to form a big chain called a polymer
75
What is a smart material?
Smart materials have properties that react to changes in their environment.
76
What is crushing?
- A way to extract plant oil
| - a seed is crushed to release oil
77
What is distillation?
Distillation is a process that can be used to separate a pure liquid from a mixture of liquids. It works when the liquids have different boiling points.
78
What is good about vegetable oils?
- provide energy and other nutrients
- contains essential fatty acids
- higher boiling point than water (good for cooking)
- give flavour
- can be used for fuels
79
What are monounsaturated fats?
Monounsaturated fats have one double bond in each fatty acid
80
What are polyunsaturated fats?
Polyunsaturated fats have many double bonds.
81
How do you test for unsaturation?
add bromine water:
- the alkene decolourises it
- the alkane stays orange-brown colour
82
Why is hydrogenation needed?
unsaturated oils are liquid at room temperature which is not very useful.
hydrogenated oils also last for a longer time
83
What are the conditions needed for hydrogenation?
- 60 degrees
| - nickel catalyst
84
What happens during hydrogenation?
hydrogen gas is added and removes the double bonds
85
What is an emulsion?
lots of droplets of one liquid suspended in another
86
What is an emulsifier?
Emulsifiers are substances that stabilise emulsions, stopping them separating out.
e.g. egg yolk
87
What is the hydrophilic head?
the water loving head, that forms chemical bonds with water but not with oils
88
What is the hydrophobic tail?
the water hating tail, that forms chemical bonds with oils but not with water.
89
What is wegners theory?
that the Earth's continents were once joined together, but gradually moved apart over millions of years.
90
What evidence did wegner have for his theory?
- fossils of very similar plants and animals found on opposite sides of the Atlantic ocean
- 'jigsaw fit' with the the coast of south America and Africa
- matching layers of rock in both continents
91
Why was wegner not believed?
- he was an astronomer
- not enough evidence
- other theory such as the land bridge
92
Describe stage one in the evolution of the atmospher
- volcanoes
- mostly CO2, water vapour, methane and ammonia
- oceans formed why the oceans condenced
93
Describe stage two in the evolution of the atmospher
- green plants and algae evolved and produced O2 by photosynthesis.
- these plants died and formed sedimentary rocks and fossil fuels
94
Describe stage three in the evolution of the atmospher
- build-up of oxygen allowed complex organisms and the ozone layer to form
- virtually no Co2
95
What is the primordial soup theory?
in the early earths atmosphere which was rich in nitrogen, hydrogen, ammonia and methane lightening caused a chemical reaction between the gases resulting in the formation of amino acids. These collected in a body of water and the acids combined to produce organic matter which evolved into simple organisms.
96
What happens in fractional distillation of air?
- the air is first filtered
| - then it is liquefied and moved to a distillation collumn
97
what is the difference between a molecule and a compound
A molecule is formed when two or more atoms join together chemically. A compound is a molecule that contains at least two different elements. All compounds are molecules but not all molecules are compounds.
98
What changes occurred in the earths atmosphere?
* oxygen increased because plants / algae developed and used carbon dioxide for photosynthesis producing oxygen
* carbon dioxide decreased because oceans formed and dissolved carbon dioxide + carbon dioxide became locked up in sedimentaryrock and fossil fuels
* oceans formed because the Earth / water vapour cooled and water vapour in the atmosphere condensed
* continents formed because the Earth cooled forming a supercontinent / Pangaea which formed the separate continents
* volcanoes reduced because the Earth cooled forming a crust
* nitrogen formed because ammonia in the Earth’s early atmosphere reacted with oxygen
99
How is steel made?
Carbon is removed from molten iron by blowing oxygen into it. The oxygen reacts with the carbon, producing carbon monoxide and carbon dioxide, which escape from the molten metal.
100
High-carbon steels
have 1.5% carbon
high-carbon steels are hard and inflexible
used for tools such as hammers
101
Stainless steel
iron mixed with chromium or nickel
stainless steels are resistant to corrosion.
used for cutlery and kitchens
102
How is distillation used to extract plant oils?
dissolved in a solvent then boiled which refines the oil and removes water, solvents and impurities
103
how do the economics of metal extraction change?
- market price of the metal may drop/ increase
| - technology improvements make it possible to extract more metal from rock than originally possible
104
How are ores concentrated?
rocky materials are removed
105
What are the negatives of electrolysis?
uses a lot of energy. For Example, high temperatures are needed to melt the metal
106
Why is recycling metal important?
- takes a lot of energy which comes from burning fossil fuels (expensive)
- fossils fuels are running out and when burnt can cause acid rain, global dimming and climate change
- finite amount of each metal in the earth and recycling conserves the resources
- cuts down on rubbish going to lanfill
107
properties of copper
good conductor
ductile
hard and strong but also malleable
doesn't react with water
108
properties of aluminium
resistant to corrosion
low density
forms hard strong alloys
not strong
109
properties of titanium
low density
very strong
corrosion resistant
110
What are the first 4 alkanes in order?
Methane
Ethane
Propane
Butane
111
What is biodiesel?
vegetable oils which can be mixed with diesels to run a diesel engine.
112
What do a polymers psychical properties depend on?
temperature and pressure of polymerisation. hotter+higher pressure = more flexible and less dense
113
What are the Pros and Cons of emulifiers?
pros: stoprs emulsions from seperating out, longer shelf-life, food which is lower in fat but still has a good texture
cons: ellergic to certain emulsifiers e.g. egg yolk so ingredients have to be checked very carefully
114
Why do the tectonic plates drift?
because of convection currents in the core caused by the radioactive decay of iron and nickel
115
Who came up with the Primordial soup theory?
Miller and Urey
116
Why is the primordial soup theory not correct?
They found that amino acids were made but not as many as there are on earth.
