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Chemistry Revision > Revision > Flashcards

Revision Flashcards

1
Q

What gases are believed to have been released from volcanoes during the first billion years of the Earth’s existence?

A

Nitrogen, carbon dioxide, water vapour; small amounts of ammonia and methane.

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2
Q

How did the oceans form?

A

Water vapour in the atmosphere condensed.

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3
Q

Why did the amount of carbon dioxide in the earlier atmosphere decrease?

A

When oceans formed, carbon dioxide dissolved in the water; carbonates precipitated producing sediments, reducing carbon dioxide in the atmosphere.

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4
Q

How do you test for oxygen gas?

A

Glowing splint delights

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5
Q

What organisms increased the amount of oxygen in the Earth’s atmosphere?

A

Primitive plants/ algae.

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6
Q

Write the balanced symbol equation for photosynthesis.

A

6CO2 + 6H2O ——————> C6H12O6 + 6O2

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7
Q

Other than photosynthesis, what other factors decreased the level of carbon dioxide in the atmosphere?

A

Formation of sedimentary rocks and fossil fuels (natural gas, oil, coal).

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8
Q

Describe the main changes to the atmosphere over time and the likely causes of these changes.

A

Intense volcanic activity – water vapour, carbon dioxide, nitrogen, ammonia, methane released.
Water vapour condensed to form oceans.
Atmosphere mostly carbon dioxide; nitrogen slowly building up over time.
Carbon dioxide dissolved in oceans; carbonates precipitated producing sediments. Carbon dioxide levels in atmosphere drop.
Photosynthesis – algae produce oxygen.
Plants evolved, levels of carbon dioxide reduced, levels of oxygen increased; animals evolved.
Carbon dioxide levels dropped during the formation of sedimentary rock (from sediments) and fossil fuels (from organisms).

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9
Q

Name 3 greenhouse gases.

A

Water vapour, carbon dioxide, methane.

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10
Q

What is the link between greenhouse gases and the temperature of the Earth?

A

Greenhouse gases maintain temperatures on the Earth high enough to support life.

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11
Q

Name human activities which increase the amount of carbon dioxide in the atmosphere.

A

Burning/ combustion of fossil fuels, deforestation.

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12
Q

Name human activities that increase the amount of methane in the atmosphere.

A

Farming of livestock; landfill sites.

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13
Q

What do many scientists believe about human activities and the temperature of the Earth’s atmosphere?

A

Human activities will cause the temperature of the Earth’s atmosphere to increase at the surface resulting in climate change.

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14
Q

Why are there issues surrounding modelling human impact on climate change?

A

It is difficult to model these changes
There are uncertainties caused by the location where the measurements are taken.
Questions regarding historical accuracy.

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15
Q

Name two gases and their compositions in today’s atmosphere.

A

Nitrogen (80%), Oxygen (20%)

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16
Q

Place these metals in order of their reactivity:

Potassium, silver, copper, magnesium

A

Highest: Potassium, magnesium, copper, silver: lowest

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17
Q

Name the two non-metals in the reactivity series.

A

Carbon and hydrogen

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18
Q

Metals form positive ions. What is the scientific name for these positive ions?

A

Cations

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19
Q

Why is gold found in the Earth as an element rather than a compound?

A

It is very unreactive.

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20
Q

What is a redox reaction?

A

Reaction involving both oxidation and reduction.

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21
Q

Describe oxidation in terms of electrons.

A

oxidation is loss of electrons.

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22
Q

Describe reduction in terms of electrons.

A

reduction is gain of electrons.

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23
Q

What is an ore?

A

Metal compound in a rock.

24
Q

What is produced when metals react with oxygen?

A

Metal oxide.

25
Q

What is this process called and why?

A

Oxidation, gain of oxygen.

26
Q

What is reduction in terms of oxygen?

A

Loss of oxygen

27
Q

What type of ions do metals produce?

A

Positive

28
Q

Which is more reactive, potassium or iron?

A

Potassium

29
Q

Which two non-metals can be included in the reactivity series?

A

Carbon and hydrogen

30
Q

Why is gold found as an element in the Earth?

A

Unreactive metal

31
Q

How are metals, less reactive than carbon, extracted from their ores?

A

Reduction with carbon

32
Q

Describe oxidation in terms of electrons.

A

OIL – loss of electrons

33
Q

Describe reduction in terms of electrons.

A

RIG – gain of electrons

34
Q

Write the word equation for the reaction between lithium and water.

A

lithium + water → lithium hydroxide + hydrogen

35
Q

Write the balanced symbol equation for the reaction between lithium and water.

A

2Li(s) + 2H2O(l) → 2LiOH(aq) + H2(g)

36
Q

HT: Zinc can be extracted from zinc oxide by heating it with carbon in the blast furnace. Carbon monoxide is also produced. Which reactant is:

A

a) Oxidised? Carbon

b) Reduced? Zinc oxide

37
Q

Why is electrolysis used to extract aluminium from its ore?

A

Aluminium is more reactive than carbon.

38
Q

Why is electrolysis an expensive way to extract metal from its ore?

A

Large amounts of energy needed.

39
Q

Name the compound from which aluminium is extracted.

A

Aluminium oxide/ bauxite.

40
Q

What type of ores can phytomining and bioleaching be used on?

A

Low-grade ores

41
Q

Why are phytomining and bioleaching used?

A

Avoids traditional mining methods of

digging, moving and disposing of large amounts of rock

42
Q

How does phytomining extract metals?

A

Uses plants to absorb metal compounds,
the plants are harvested and burned,
this produces ash that contains metal compounds.

43
Q

What is a life-cycle assessment?

A

Considering the impact on the environment for a product; in the lifetime of the product.

44
Q

Life cycle assessments are carried out to assess the environmental impact. What stages of a product are covered?

A

Obtaining the raw materials
Manufacturing the product
Using the product
Disposal of the product.

45
Q

What areas of life cycle assessments can be easily quantified?

A

Use of water, resources, energy and waste production.

46
Q

How can metals be recycled?

A

Melting, recasting or reforming.

47
Q

What are three advantages of recycling metals?

A

Cheaper, reduced environmental impact, avoids need for mining.

48
Q

Where are most metals found in the periodic table?

A

Transition metals between Groups 2 and 3

49
Q

Name four properties of transition metals.

A

High melting point, high density, form coloured compounds, act as catalysts.

50
Q

What is corrosion?

A

Oxidation of metals.

51
Q

Name three ways to prevent the rusting of iron.

A

Exclusion of oxygen, exclusion of water, sacrificial protection.

52
Q

What is electroplating? What is it used for?

A

Using electricity to oat a metal with a thin layer of another metal.

53
Q

What is an alloy?

A

Metal mixed with other elements.

54
Q

How does converting a metal to an alloy improve the strength?

A

Distorts the layers in the structure making it difficult for them to slide over each other.

55
Q

What is magnalium?

A

Alloy of aluminium and magnesium.

56
Q

Name two uses of magnalium.

A

Aircraft/ car parts, pyrotechnics.

57
Q

How is iron turned into steel?

A

Addition of carbon and other substances e.g. chromium.

Chemistry Revision (7 decks)

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