Chemistry Ocr 21St Century Unit 1

Front 1

Scientific processing

Back 1

Hypothesis- Experiment- Recording- Conclusion

Front 2

Correlation

Back 2

A correlation is the relationship between two factors. Just because there is a correlation does not mean the factor causes the outcome.

Front 3

A cause

Back 3

A cause is a scientific link between two factors.

Front 4

Risk

Back 4

Everything has risk attached, people make their own decisions about whether their risk is worth the possible benefits.

Front 5

Benefits and cost

Back 5

When developing new technologies scientists weigh up benefits and costs. Benefits are the possible improvements and costs are the damage that could be produced.

Front 6

Human activity impacts on Environments

Back 6

Humans have a huge impact in their surroundings, these are often unintentional. This can include the use of non-renewable resources.

Front 7

Ethics

Back 7

Often with science people question where the limit lies. Should we be changing what some consider 'God given'? Their are two main arguments within science and ethics 1) Some people think certain actions are unnatural and unacceptable. 2) The right decision is the one that brings the greatest benefits.

Front 8

Evolution of the atmosphere Phase 1
(Volcanoes)

Back 8

The Earth's surface was originally molten. It slowly cooled down creating a thin crust but volcanoes were still erupting. Volcanoes produced a lot of gas (carbon dioxide, water vapour and nitrogen) this is what made our early atmosphere form, this atmosphere was mainly carbon dioxide. The oceans were formed when water vapour condensed against the cool crust.

Front 9

Evolution of the atmosphere Phase 2
(Green plants)

Back 9

Green plants began to form and they were thriving in the high carbon dioxide levels. Lots of this carbon dioxide was dissolved into the formed oceans and replaced by oxygen formed in photosynthesis.

Front 10

Evolution of the atmosphere Phase 3
(Complex organisms)

Back 10

The build up of oxygen kills off some of the early simple organisms but allows more complex ones to grow.

Front 11

Atmospheric mixture

Back 11

Nitrogen 78%
Oxygen 21%
Argon 1%
-These vary slightly dependent on environment.

Front 12

Human affect on the atmosphere

Back 12

Nitrogen, Oxygen and Argon levels stay pretty consistent however human activity adds small amounts of pollutants.

Front 13

Atoms

Back 13

All substances are made from tiny particles called atoms.

Front 14

Molecules

Back 14

Molecules are formed when atoms are joined together.

Front 15

Hydrocarbons

Back 15

Fossil fuels are hydrocarbons which means they only contain two elements: carbon and hydrogen. Coal is NOT a hydrocarbon (its just carbon).

Front 16

Combustion

Back 16

Burning is also known as combustion, you can get incomplete and complete combustion.

Front 17

Oxidisation

Back 17

Burning fuels is an example of oxidisation. oxidisation is a reaction where oxygen is added (eg: carbon+ oxygen gives carbon dioxide)

Front 18

Reduction

Back 18

Reactions where oxygen is lost.

Front 19

Air pollution- Carbon

Back 19

All fossil fuels contain large amounts of carbon.
Carbon Dioxide- An atmospheric pollutant that contributes to the greenhouse effect.
Carbon Monoxide- Produced when not enough oxygen is present in the burning of fuels. It is a poisonous gas.
Particulate Carbon- Tiny particles produced in incomplete combustion of fuels. They float about in the atmosphere until they settle as soot.

Front 20

Air Pollution- Sulphur

Back 20

Sulphur pollution comes from the impurities of fuel, when fuel burns sulphur burns as well, this usually ends up in the atmosphere as sulphur dioxide. Sulphur dioxide causes acid rain when it reacts with the water vapour in the air. Acid rain causes detrimental effects to the environment.

Front 21

Air Pollution- Nitrogen

Back 21

Nitrogen pollution doesn't come from fuels it comes when the nitrogen that is already present in the air is burned.
Nitrogen monoxide- formed when nitrogen and oxygen are burnt at high temperatures (this happens in car engines)
Nitrogen Dioxide- Once nitrogen monoxide reacts with the air it becomes nitrogen dioxide.
This can cause nitric acid to form within the clouds contributing to acid rain.

Front 22

Acid Rain

Back 22

Formed when the pollutants nitrogen dioxide and sulphur dioxide react with water vapours causing the formation of nitric or sulphuric acid to be produced and fall within the rain. This causes excessive damage to an environment.

Front 23

Reducing pollution from power stations

Back 23

Pollution can be produced by using less electricity. The less electricity we use the less fossil fuels need to be burnt. Purer fuel would prevent sulphur from being burnt. Sulphur dioxide and particulates can be removed from the flue gases. 1) Seawater- The sulphur dioxide is dissolved in seawater producing carbon dioxide, water and dissolved sulfate. 2)An alkaline slurry (eg: calcium oxide in water)- The slurry is sprayed onto the gases and the sulphur dioxide reacts with the calcium oxide forming calcium sulfite.

Front 24

Catalytic converters

Back 24

Transfer harmful gases into less harmful gases. They convert nitrogen monoxide into nitrogen and oxygen. They also convert carbon monoxide into carbon dioxide.

Front 25

Biofuels

Back 25

Biofuels are a renewable energy source that are made from plants and waste, they only produce carbon dioxide and water when burnt and are carbon neutral. However using large amounts of these plants could result in loss of habitats for animals.

Front 26

Battery power

Back 26

Electric cars produce no exhaust emission but they need recharging and electricity still burns fossil fuels so no pollution is actually taken away.