Chemistry 1 - Core Flashcards

1
Q

What is the Earth surrounded by a thin layer of?

A

Atmosphere

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2
Q

What does the atmosphere contain?

A
78% nitrogen
21% oxygen
1% argon (other noble gasses) 
Small amounts - water vapour, carbon dioxide and particulates)
CO2 - 0.035%
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3
Q

When was the Earth formed?

A

4.6 billion years ago

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4
Q

What did the earliest atmosphere contain?

A

Ammonia, water vapour, carbon dioxide

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5
Q

How did the seas form?

A

From water vapour in the atmosphere

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6
Q

What lead to the decrease in atmospheric carbon dioxide, and increase in oxygen?

A

The evolution of photosynthesising organisms

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7
Q

What happened to carbon dioxide after it dissolved in the oceans?

A

Carbon became locked up in sedimentary rocks as carbonates and fossil fuels

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8
Q

What are pollutants?

A

Chemicals that harm the environment and our health

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9
Q

What can pollutants affect directly?

A

Food chains, health etc

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10
Q

How can pollutants have an indirect effect?

A

Through acid rain etc - it causes things which in turn have an effect

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11
Q

What is carbon dioxide harmful to and how?

A

The environment - traps heat in the earths atmosphere - leading to global warming

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12
Q

What is nitrogen oxide harmful to and how?

A

The environment and humans - can cause acid rain and breathing problems and make asthma worse

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13
Q

What is sulfur dioxide harmful to and how?

A

The environment and causes acid rain

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14
Q

What is carbon monoxide harmful to and how?

A

Humans - displaces oxygen in blood - binds to oxygen cite on red blood cell permanently

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15
Q

What are particulates harmful to and how?

A

Environment, humans, make buildings dirty - make asthma and lung infections worse if inhaled

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16
Q

How is pollutant concentration measured?

A

In Parts Per Million (ppm) and Parts Per Billion (ppb)

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17
Q

What can affect the measuring of pollutants?

A

1- variables (volume of traffic and weather)
2- measuring equipments accuracy
3- use of skill (will effect the use of accuracy and precision)

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18
Q

What are outliers?

A

They do not follow the general pattern of data - normally indicate some form of error

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19
Q

Why is it important to repeat measurements?

A

A single set of data may not be reliable - you cannot tell

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20
Q

How can you overcome small variations and get an estimate of the true value?

A

By calculating the mean

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21
Q

Where do the carbon monoxide emissions come from?

A

Around half from road transport, the rest from homes and other idustries

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22
Q

What is the correlation between carbon monoxide in the city and in the country park?

A

The mean carbon monoxide in the city is significantly higher than the park, supporting the theory it is produced by humans

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23
Q

What are elements?

A

The building blocks for all materials

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24
Q

How many elements are there?

A

Over 100

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25
Q

What are elements made up of?

A

Very tiny particles called atoms

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26
Q

What is specific about the atoms in one element?

A

They are all the same, and are unique to that element

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27
Q

What happens when atoms join together?

A

They form bigger building blocks called molecules

28
Q

How are compounds formed?

A

When the atoms of two or more elements join chemically

29
Q

What are chemical symbols and numbers used for?

A

To write formulae

30
Q

What do formulae show?

A

The different elements that make up compound

The number of atoms of each different element in each molecule

31
Q

What happens during a chemical reaction?

A

New substances are formed from old ones

32
Q

Why are new substances formed during a chemical reaction?

A

The atoms in the reactants (starting substances) are rearranged in some wau

33
Q

Can chemical changes be reversed?

A

Not easily

34
Q

What is oxidation?

A

A chemical reaction that occurs when oxygen joins with an element or compound

35
Q

What is reduction?

A

When oxygen is lost from a substance

36
Q

What is combustion?

A

A chemical reaction that occurs when fuels burn, releasing energy as heat

37
Q

What must be present for combustion to take place?

A

Oxygen

38
Q

What is combustion an example of?

A

Oxidation

39
Q

What is coal?

A

A fossil fuel containing mostly carbon

40
Q

What is not produced during a chemical reaction?

A

Atoms

41
Q

What happens to the number of atoms during a reaction?

A

It remains the same on either side of the equation - maintain mass

42
Q

What is one result of the conservation of atoms during a reaction?

A

The production of some pollutants

43
Q

Fossil fuels consist mainly of what compounds?

A

Hydrocarbons

44
Q

What causes a burning reaction to be more rapid?

A

When fuel burns in pure oxygen rather than air

45
Q

What is causes when a fuel is burned without the presence of enough oxygen?

A

Incomplete combustion

46
Q

What does incomplete combustion lead to?

A

The production of carbon particulates or carbon monoxide

47
Q

What can high temperatures during fuel combustion lead to?

A

Nitrogen in the atmosphere reacting with oxygen to form nitrogen oxides

48
Q

What are the stages of nitrogen oxides production?

A

nitrogen reacting with oxygen - produce nitrogen monoxide

nitrogen monoxide is then oxidised - produce nitrogen dioxide

49
Q

What are NO and NO2 called when together?

A

oxides of nitrogen (written as NOx)

50
Q

What happens to carbon particulates once in the atmosphere?

A

They are deposited on surfaces (buildings etc) making them dirty

51
Q

What happens to carbon dioxide when in the atmosphere?

A

Some is removed by plants during photosynthesis, some dissolves in rain and sea water where it reacts with other chemicals in the water

52
Q

Each year what happens to the amount of atmospheric carbon dioxide?

A

It rises as we are producing too much to use up naturally

53
Q

What produces acid rain?

A

Sulfur dioxide and nitrogen dioxide dissolved in water

54
Q

What can acid rain do?

A

Cause damage to trees, erode stonework, corrode metal, upset pH balance of rivers and lakes - if water is too acidic, plants and animals will die - effecting entire food chain

55
Q

How do scientists find out exactly how air quality affects up?

A

By looking for correlations that might link a factor to an outcome

56
Q

How do scientists specify the outcomes to individual factors?

A

By carrying out secondary tests, eliminating all other variables

57
Q

How do you know if results are reliable?

A

When the test can be repeated multiple times and receive the same outcome

58
Q

Emissions from power stations can be removed by?

A

1- using less electricity so fewer fossil fuels need to be burned
2- removing toxic chemicals before they are burned
3- using alternative, renewable sources of energy
4- using a filter system to remove sulfur dioxide and particulates from flue gasses before they leave a coal burning power stations chimney

59
Q

How is sulfur dioxide removed from flue gases?

A

By wet scrubbing using an alkaline slurry or seawater

60
Q

What happens during wet scrubbing?

A

The sulfur dioxide in the flue gas is dissolved when contacted by a slurry of either lime stone (calcium carbonate) or lime (calcium oxide) and water. The absorbed sulfur dioxide is converted into calcium sulfate.

61
Q

What happens during sea water scrubbing?

A

Sulfate salts are produced when the acidic dissolved sulfur oxides, produced when the sulfur oxides react with sea water, react with alkalis.

62
Q

Emissions from motor vehicles can be reduced by?

A

1- buying a car with a more modern engine which is more efficient and burns less fuel
2- buying a hybrid car - uses electric power in the cities/ fuel for longer journeys
3- using a low sulfur fuel
4- converting the engine to run on biodiesel, a renewable fuel
5- using public transport to reduce the vehicles
6- ensuring cars are fitted with catalytic converters

63
Q

What is a catalytic converter?

A

It reduces the amount of CO2 and nitrogen monoxide emitted - contains a catalyst in the exhaust of a vehicle which converts pollutant gases into less harmful ones

64
Q

What are the benefits of recycling?

A

Helps to conserve natural resources

Saves energy - takes around 95% less energy to recycle and aluminium can than to make a new one

65
Q

What has to happen when making national choices?

A

The benefits and needs must be weighed up against the problems