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Science Year 8 > Earth > Flashcards

Earth Flashcards

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Biology 101 flashcards
1
Q

How much of the atmosphere is oxygen?

A

21%

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2
Q

How much of the atmosphere is nitrogen?

A

78%

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3
Q

How much of the atmosphere is argon?

A

1%

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4
Q

How much of the atmosphere is Co2?

A

0.03%

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5
Q

How much of the atmosphere is other gasses?

A

0.17%

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6
Q

What is the greenhouse effect?

A

The greenhouse effect is the trapping of the heat in the Earths atmosphere by certain gasses

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7
Q

What gasses cause the greenhouse effect?

A
  • carbon dioxide
  • methane
  • Nitrous oxides
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8
Q

What normally happens with the suns radiation?

A

It passes through the atmosphere, absorbed by the earths surface and re-radiated as heat

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9
Q

How does the greenhouse effect affect earth?

A

The gasses prevent the thermal energy radiating out of the earths atmosphere, causing it to heat up

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10
Q

How is the greenhouse effect affecting us? (6 factors)

A
  • polar ice sheets melting- causing sea levels to rise
  • some areas having less water - causing droughts, food shortages and desertification
  • longer growing seasons- faster crop growth due to Co2 levels rising
  • severe weather events
  • tropical diseases
  • agricultural pests - thriving In the warmer environment
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11
Q

What is the carbon cycle?

A

How carbon moves between stores through various processes

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12
Q

Name 5 processes In the carbon cycle

A
  • respiration
  • photosynthesis
  • combustion
  • feeding
  • decomposition
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13
Q

What are carbon sinks?

A

Where carbon can be stored
(e.g ocean,plant matter,soil etc.)

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14
Q

Name 5 natural recourses

A
  • biological resources (plants and animals)
  • land
  • fossil fuels
  • metal ores and other minerals
  • water
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15
Q

Define renewable resources

A

Resources that are naturally replenished within a human lifetime

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16
Q

Define non renewable resources

A

Resources that will run out or will not be naturally replenished during a human lifetime

17
Q

What is the reactivity series used for?

A

The reactivity of a metal determines the method of extraction

18
Q

In order, name the metals in the reactivity series (remember the pneumonic )

A

Potassium
Sodium
Calcium
Magnesium
Aluminium
Carbon
Zinc
Lead
Copper
Silver
Gold

19
Q

If a metal is above carbon on the reactivity series, how will it be extracted?

A

By electrolysis

20
Q

If a metal is below carbon ( not including gold or silver ) how will it be extracted?

A

By reduction using carbon (e.g)

21
Q

What two metals do not need to be extracted and why?

A

Silver and Gold because they occur native

22
Q

How does electrolysis work?

A

The ore is melted and electricity passed through it - this separates it into the metal and oxygen

23
Q

How does reduction work

A

Heating the ore with carbon will cause the carbon to react with the oxygen and leave the metal behind

24
Q

What is reduction also called?

A

Carbon displacement

25
Q

Other than gold and silver what other metal is found natively?

A

Platinum

26
Q

Name 4 pros of recycling metals

A
  • relatively easy
  • saves valuable raw materials- reserves of metal ores will last longer
  • less energy is needed to produce a metal
  • less damage to the environment- fewer quarries and mines,less noise and less heavy traffic
27
Q

Name one way of recycling plastics that can be heated and remoulded into a new shape

A

Thermosoftning ( e.g acrylic )

28
Q

How can plastics that cannot be easily remoulded be recycled

A

Thermosetting ( e.g. PET )

29
Q

What is sustainability?

A

The ability for the natural world and human civilisation to coexist indefinitely

30
Q

How can sustainability be reached?

A

The resources we use are replenished/recycled and have little impact on the environment

31
Q

Is it more energy efficient to extract or recycle materials?

A

Some products use nearly ,as much energy as is needed to extract, collecting and processing the material, however generally it is more efficient to recycle

32
Q

What is an example of a material where it is more expensive to recycle?

A

Glass - recycling glass saves 30% of the energy needed to make new glass but the cost of setting up and running a glass recycling centre means it is more expensive

33
Q

What is an example of a material that recycling it is profitable and saves a lot of energy?

A

Aluminium - recycling aluminium saves 95% of energy and is highly profitable

34
Q

What is down cycling?

A

When the material is recycled and a new product is made that itself cannot be recycled

Science Year 8 (7 decks)

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