C2 - Chemical Resources Flashcards

1
Q

What is the lithosphere?

A

The crust and upper part of the mantle.

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2
Q

How can we use seismic waves to understand the structure of the Earth?

A
  • S-waves can travel through the mantle, which shows that it’s solid. S-waves can only travel through solids.
  • S-waves not detected in outer core’s shadow, suggesting is is liquid.
  • P-waves travel faster through the middle of the core, suggesting the inner core is solid.
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3
Q

Describe the evidence found that proves continental drift theory.

A
  • Mid-Atlantic Ridge discovered.
  • Evidence found of magma rising up from sea bed.
  • Creatures with same genetic history found on multiple continents.
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4
Q

Explain how two plates can collide and cause a volcanic eruption?

A
  • Crust on the ocean floor is denser than the crust below the continents.
  • The dense oceanic plate is forced (subducted) underneath the less dense continental plate.
  • These regions are generally cooler and therefore more dense, so they sink really easily.
  • As the oceanic plate is forced down, it melts and the molten rock starts to rise.
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5
Q

What are igneous rocks?

A

They are rocks made when any sort of molten rock cools down and solidify.

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6
Q

Explain how the rate of cooling effects the crystallization of igneous rocks.

A

If the molten rock cools over a longer period of time, the crystals on the igenous rock will larger and more defined - this is because the interlocking crystal structure will have had longer to form.

On the other hand, fast-cooling molten rock will generally become igneous rocks with smaller crystals.

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7
Q

What igneous rock is produced from runny lava from fairly safe eruptions?

A

Iron-rich basalt

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8
Q

What igneous rock is produced from thick, viscous lava released from explosive eruptions?

A

Silica-rich rhyolite

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9
Q

Explain the formation of sedimentary rock.

A
  1. Layers of sediment are deposited in lakes or seas.
  2. Over millions of years, these layers are buried under the weight of more layers of material. This weight squeezes the water from inside the sedimentary layers.
  3. Fluids flowing through the pores deposit natural mineral cement.
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10
Q

What is the symbol equation for the thermal decomposition of limestone?

A

CaCO3 -> CaO + CO2

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11
Q

Explain the formation of metamorphic rocks.

A
  1. Formed from the action of heat and pressure on other rocks over long period of time.
  2. As long as rocks don’t melt, they’re considered metamorphic.
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12
Q

Give an example of a metamorphic rock and explain its properties.

A

Marble:

  • Just another form of calcium carbonate.
  • Heat and pressure break down the limestone and it reforms as small crystals.
  • As a result, the marble is much harder.
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13
Q

Name an igneous rock and explain its properties.

A

Granite:

  • Various minerals randomly arranged in a structure of interlocking crystals.
  • As a result, granite is very hard.
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14
Q

How is glass made?

A

Limestone is heated up with sand (silicon dioxide) and soda (sodium carbonate) until it melts.

When the mixture cools, it comes out as glass.

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15
Q

How does clay form?

A

Formed from weathered and decomposed rocks.

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16
Q

How do we make bricks?

A

Bricks are hardened forms of clay.
We put clay under very high temperatures, hardening them - as a result, bricks can withstand lots of weight (great for stacking).

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17
Q

How do we make cement?

A
  • Limestone and clay heated together.

- Water slowly reacts with cement, making it harden gradually.

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18
Q

Why is reinforced concrete stronger than ordinary concrete?

A

Steel rods are inserted into the concrete, combining the hardness of the concrete with the strength (tensile strength) and flexibility of steel.

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19
Q

What is a composite material?

A

A combination of two materials.

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20
Q

Explain how electrolysis is used to purify copper.

A
  • An impure positive annode and a pure negative cathode.
  • In a solution (the electrolyte) of copper (II) sulfate, containing lots of Cu^2+ ions.
  • Electrons pulled off from the copper atoms at the anode, leaving positive Cu^2+ copper ions in the solution.
  • These positive ions are attracted to the negative cathode. They offer their electrons to the cathode, turning the Cu^2+ ions back into copper atoms that are then deposited at the cathode.
  • Impurities dropped at the anode as sludge.
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21
Q

What process happens at the cathode? What is the ionic half equation?

A

Reduction (gain of electrons):

Cu2+ + 2e– → Cu

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22
Q

What process happens at the anode? What is the ionic half equation?

A

Cu → Cu^2+ + 2e-

23
Q

What is an alloy?

A

A mixture of a metal and other elements.

For example:

  • A metal and metal
  • A metal and a non-metal
24
Q

What is steel? What are its advantages

A

Steel is an alloy of iron and carbon. This is an advantage as steel is a lot harder than iron and less likely to rust than iron on its own.

25
Q

What is solder?

A

An alloy of lead and tin.

26
Q

What is amalgam?

A

An alloy of mercury, used in dentistry for filling teeth.

27
Q

What is brass?

A

An alloy of copper and zinc, used in musical instruments.

28
Q

Describe the features of a specific smart alloy.

A

Nitinol is a smart alloy that has shape memory. It can be bent and twisted before turning back to its original shape.

29
Q

Compare the properties of iron and aluminium.

A
  • Iron is more dense than aluminium.
  • Iron is magnetic, aluminium is not.
  • Iron corrodes (rusts) easily and aluminium does not.
  • Iron and aluminium are both malleable.
  • Iron and aluminium are both good conductors.
30
Q

What is the word equation for the rusting of iron?

A

Iron + Water + Oxygen –> Hydrated iron(III) oxide

31
Q

Why doesn’t aluminium corrode (rust) when wet?

A

Aluminium doesn’t corrode when wet because it’s much more reactive than iron, meaning it reacts quickly with the oxygen in the air to form aluminium oxide. This aluminium oxide works as a protective layer than sticks to the material and stops the rusting reaction from occurring.

32
Q

What factors effect the rate of rusting?

A

Salt water or acid rain will speed up the rusting process.

33
Q

Describe advantages and disadvantages of using aluminium rather than steel to manufacture a car.

A

Advantages:

  • Car body of same size will be lighter with aluminium.
  • Car body with aluminium will corrode less.
  • Aluminium is more expensive.
34
Q

Describe an advantage and disadvantage of recycling materials used to make cars?

A
  • Helps save limited natural resources.

- Non-metal materials need to be separated before they can be recycled. This costs money.

35
Q

What is the word equation for neutralisation?

A

acid + base –> salt + water

36
Q

What is the ionic half equation for neutralisation?

A

H+ + OH-⇌ H2O

37
Q

Why do all metal oxides and metal hydroxides react with water?

A

They are bases, so when dissolved in water, are alkalis.

Therefore, they react with acids to form a salt and water.

38
Q

What is the symbol equation for the neutralisation reaction between hydrochloric acid and copper oxide?

A

HCl + CuO —> CuCl2 + H2O

39
Q

What is the symbol equation for the neutralisation reaction between nitric acid and sodium hydroxide?

A

HNO3 + NaOH –> NaNO3 + H2O

40
Q

What is the symbol equation for the neutralisation reaction between sulphuric acid and calcium carbonate?

A

H2SO4 + CaCO3 —> H2O + CO2 + CaSO4

41
Q

What is the symbol equation for the neutralisation reaction between nitric acid and ammonia?

A

HNO3 + NH3 —> NH4O3

42
Q

What is the general word equation for a reaction between an acid and ammonia?

A

Acid + Ammonia –> Ammonium salt

43
Q

Why do fertilisers need to be dissolved in water?

A

So that they can be absorbed by the plants’ roots.

44
Q

How do fertilisers increase crop yield?

A
  • Replaces elements needed by plant that have been used up by previous crops.
  • More nitrogen available means that plants can build more proteins and therefore grow larger.
45
Q

Explain the process of eutrophication?

A
  • Leaching/run-off of fertiliser into streams.
  • Increased nitrate or phosphate in river.
  • Algal bloom as they have more nitrogen, so can grow/reproduce more.
  • Growth of algae blocks off sunlight to plants underwater.
  • Aerobic bacteria reproduce rapidly as they feed on the dying plants. The growing population of aerobic bacteria means that oxygen is used up in the water.
  • As a result, other living organisms start dying.
46
Q

How can you prepare ammonium nitrate in the lab?

A

Solution of ammonium and an indicator are kept in a flask. Above the flask, is a burette containing a nitric acid solution.

Slowly, drops of nitric acid are added to the ammonium solution. As soon as the indicator changes colour, stop adding the the nitric acid - the neutralisation reaction ahs finished.

To obtain a solid fertiliser product, the solution must slowly evaporate and then be left to crystalise. To get pure ammonium nitrate crystals without the indicator, the titration must be repeated with that exact volume of acid.

47
Q

What is the symbol equation for reaction in the Haber Process?

A

N2 + 3H2 ⇌ 2NH3

48
Q

How does pressure affect the percentage yield of the Haber Process?

A

Pressure favours the forward reaction, so the higher the pressure - the greater the percentage yield.

49
Q

How does temperature affect of the percentage yield of the Haber Process?

A

Temperature favours the reverse reaction, so the higher the temperature - the smaller the percentage yield.

50
Q

What is the optimum temperature used in the Haber Process? Why is that temperature the optimum one?

A

450 degrees Celsius:

  • Fast rate of reaction
  • Reasonable percentage yield
  • It’s a compromise
51
Q

What catalyst is used in the Haber Process? How does this catalyst affect the reaction?

A

Iron catalyst:

  • Speeds up rate of reaction
  • Therefore, temperatue does not need to be raised as high (which is good, as higher temperature decreases percentage yield).
52
Q

How is solution mining used to extract salt?

A

Hot water is pumped underground, dissolving the salt. The salt solution is then forced to the surface via the pressure of the water.

53
Q

Describe the electrolysis of brine (sodium chloride solution).

A

The sodium chloride solution contains four different ions, Na+, OH-, Cl- and H+. At the cathode, H+ ions gain electrons to produce hydrogen gas. At the anode, Cl- ions lose electrons to form chlorine gas.