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Flashcards in C1 Part A Deck (67)
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Give the symbol equation for the thermal decomposition of limestone:

CaCO→ CaO + CO2


Which other substances thermally decompose in the same way as limestone?

Magnesium, copper, zinc and sodium carbonate


Give the word and symbol equation  for the reaction that causes limestone to be damaged by acid rain.

Calcium Carbonate + Sulfuric acid → Calcium sulfate + Carbon dioxide + Water


CaCO3 + SO→ CaSO4 + CO+ H2O



What product is formed when you react calcium carbonate with water?

Calcium Hydroxide


Calcium hydroxide is an alkali which means it can be used to neutralise....... and does this much faster than ............

It is also used to indicate the presence of ........... when ......... . It becomes ........... if there's ........ and this is due to the formation of ............ 

  • Used to neutralise acidic soil in fields and does this much faster than powdered limestone
  • Indicates the presence of Carbon Dioxide when gas is bubbled through it. It becomes cloudy if there's Carbon Dioxide in the gas - this is due to the formation of Calcium Carbonate.


How is powdered clay used to make cement and what happens when cement is mixed with sand and water?

It is heated in a kiln with clay. When cement is mixed with sand and water it becomes mortar.


What happens when clay is mixed with sand and aggregate?

Concrete is made


List the issues with quarrying limestone (5)

  • Huge holes change the landscape permanently (however restoration of the area is usually required after quarrying work has been finished)
  • Quarrying processes (eg. blasting rocks apart with explosives) make a huge amount of noise
  • Quarrying destroys habitata
  • Limestone must be transported elsewhere to be made into other products, creating more noise and pollution.
  • Waste materials produce unsightly tips


How do cement factories harm people and the environment? (2)

  • They create a lot of dust, which can cause breathing problems.
  • A huge amount of energy is needed, most of this will come from burning fossil fuels (which pollutes the atmosphere).


What are the informal names for Calcium Oxide and Calcium Hydroxide?

Calcium Oxide: Quicklime

Calcium Hydroxide: Slaked lime


What are some of the uses of Limestone products? (5)

  • Concrete and cement are building materials
  • Chemicals can be used in dyes, paints and medicine
  • Used to neutralise acidic soil, lakes and rivers
  • In power station chimneys to neutralise sulfur dioxide (a cause of acid rain)


Why is limestone so widely used? (4)

  •  It is cheaper than granite or marble
  • Fairly easy to cut
  • More hardwearing than marble
  • Limestone, concrete and cement don't rot like wood does when it gets wet and they're fire-resistant.


List some advantages (3) and disadvantages (3) of concrete


  • Can be poured into moulds
  • It's cheap
  • Concrete doesn't corrode and it's fire resistant


  • Emissions from the concrete and cement industry contribute to the greenhouse gas effect (and climate change)
  • Concrete has a low tensile strength and can crack, meaning often it must be reinforced with steel bars
  • It's deemed to be ugly as a building material




What is a metal ore?

A rock that contains enough metal for it to be worthwhile extracting


What is the main aluminium ore, name and symbol?

Bauxite, aluminium oxide



Which two economic factors contribute to how worthwhile extracting a metal is?

  • The market price of the metal (if it drops, it might not be worth extracting)
  • Improvements in technology mean that extraction that might not have been worthwhile in the past, now is


By which two methods can metals be extracted from their ores?

Chemically (by reduction)

By Electrolysis


Some metals can be extracted from their ores by reduction with ................ When an ore is reduced, this means ............ has been removed from it.

Some metals can be extracted from their ores by reduction with carbon. When an ore is reduced, this means oxygen has been removed from it.


Which metals can be extracted using reduction? (4)

Those lower in the reactivity series than carbon:

Zinc, Iron, Tin, Copper


Give the symbol and word equation for the reduction process used to extract iron.

Where does this occur in industry?

2Fe2O3 + 3C → 4Fe + 3CO2

Iron (III) Oxide + Carbon → Iron + Carbon Dioxide
In a blast furnace


Which metals are extracted by electrolysis? (5)

Those higher in the reactivity series than carbon:

Potassium, Sodium, Calcium, Magnesium, Aluminium


Why is electrolysis much more expensive than reduction?

It requires a lot of energy, both to melt the ores and charge the elctrodes.


How else is electrolysis used, other than for extraction? Give an example that includes a specific metal

Purification of metals

Copper produced by reduction is impure. Electrolysis is used to form a very pure copper, which is much better at conducting.


What is an electrolyte and how do they conduct electricity?

A liquid used to conduct in the process of electrolysis, often metal salt solutions made from the ore of the metal being extracted or molten metal oxides.

Electrolytes have free ions that enable electricity to be conducted.


Explain the process of electrolysis specific to copper, draw a diagram if it helps (3 main steps)


Anode - positive electrode

Cathode - negative electrode

  • Electrons are taken from copper atoms at the anode, causing them to enter the copper sulfate solution (electrolyte) as Cu2+ ions.
  • Cu2+ ions near the cathode gain electrons and become copper atoms
  • Impurities are left at the anode as a sludge, pure copper atoms bond to the cathode.



In copper electrolysis, what are the cathode and anode made of?

Cathode - Begins as a thin strip of pure copper that grows as electrolysis occurs

Anode - a lump of impure copper that will dissolve


Outline how displacement reactions can be used to extract metals

  • If a more reactive metal is placed in a metal compund, it will replace the less reactive metal in the compound
  • More reactive metals bond more strongly to the non-metal part of the compound, meaning the less reactive metal is pushed out


Give the word equation for how iron is used in a displacement reaction to extract copper and explain why this is useful?

Why can silver not be used to extract copper?

  • Copper sulfate + Iron → Iron sulfate and copper
  • Useful because iron is cheap but copper is expensive.
  • Silver cannot be used because it is less reactive than copper. 


Why are scientists looking into new ways to extract copper from low grade ores?

Copper-rich ores are in short supply but demand is growing


What is bioleaching? Describe the process

The use of bacteria to separate copper from copper sulfide.

Bacteria extracts energy from the bonds between the copper and sulfur. Leachate is produced, this contains copper that can be extracted (eg. by filtering).