Carbonates and The Atmosphere

Question 1

Reaction of Calcium Oxide and hydrochloric acid

Answer 1

CaO + 2HCl -> CaCl2 + H2O

Question 2

Thermal decomposition of calcium carbonate

Answer 2

CaCO3 -> CaO + CO2

Question 3

Reaction of Calcium Hydroxide and Hydrochloric acid

Answer 3

Ca(OH)2 + 2HCl -> CaCl2 + CO2 + 2H2O

Question 4

Thermal decomposition of calcium hydrogencarbonate solution

Answer 4

Ca(HCO3)2 -> CaCo3 + H2O + CO2

Question 5

Complete combustion of pentane (C5H12)

Answer 5

C5H12 -> 5CO2 + 6H2O

Question 6

Carbon dioxide reacting with lime water

Answer 6

Co2 + Ca(OH)2 -> CaCo3 + H2O

Question 7

Reaction of methane in a limited supply if oxygen

Answer 7

2CH4 + 3O2 -> 2 Co2 + 4H2O

Question 8

Dry air consists of:

Answer 8

78% Nitrogen
21% Oxygen
1% Other gases (0.039% Co2 and 0.93% argon)

Question 9

What is meant by thermally decomposing?

Answer 9

Breaks down on heating

Question 10

Chemical name of limewater

Answer 10

Calcium Hydroxide

Question 11

How is carbon monoxide sometimes produced in the home and why is it dangerous?

Answer 11

• Colourless, tasteless and has no smell
• Binds with the haemoglobin rather than oxygen
• Caused by poor ventilation, burning coal and gas or boilers

Question 12

Explain why boiling removes hardness in the water caused by calcium hydrogencarbonate and state what would be observed

Answer 12

Ca(HCO3)2 -> CaCo3 + H2O + Co2

• Ca2+ becomes part of the solid CaCo3
• Ca2+ is removed from the solution
• Observe white precipitate (limescale)

Question 13

Uses of calcium carbonate:

Answer 13

• Neutralise soils
• Neutralise gases from power station emissions
• Neutralise excess stomach acid

Question 14

How has carbon dioxide in atmosphere changed over the past 200 years?

Answer 14

• Been an increase in Co2
• Global temperature has increased
• Correlation, but not necessarily a link
• There are serious consequences (the precautionary principle)

Question 15

Explain iron seeding

Answer 15

Iron seeding of the oceans fertilise the phytoplankton that can photosynthesise and absorb large amounts of carbon dioxide

Question 16

Other method of reducing carbon dioxide in atmosphere

Answer 16

Developing means of converting carbon dioxide into hydrocarbons that can be reused as fuel

Question 17

Ways to reduce carbon dioxide emissions:

Answer 17

• Use less energy e.g use cars less and recycle waste

* Use alternate forms of energy production such as wind farms, wave power and nuclear

Question 18

How long ago did the earth form

Answer 18

Almost 4.5 billion years ago

Question 19

What has caused the amount of Co2 in the atmosphere to decrease since 4.5 billion years ago?

Answer 19

• Some CO2 dissolved into the oceans
• Carbon dioxide was incorporated into marine organisms through the food. They eventually formed to carbonate rocks
• Primitive plants started to photosynthesise and converted the CO2 into oxygen

Question 20

Why is the atmosphere changing slowly?

Answer 20

• Volcanic eruption
• Farming
• Deforestation
• Increased combustion

Question 21

Uses of Limestone (CaCo3)

Answer 21

• Building material and in manufacturing of iron
• Glass - heated with sand and soda
• Cement - heated with clay in a kiln
• Concrete - mixed with sand, water and crushed rock
• Mortar - mixed with sand and water

Question 22

What happens in an ion exchange resin?

Answer 22

Salt is added to the resin and as the water passes over, the Ca2+ and Mg2+ ions are replaced with Na+ ions from the salt. The waste is CaCl2 and MgCl2 is washed away

Question 23

How is limestone obtained?

Answer 23

By quarrying

Question 24

Reaction of Calcium Carbonate and Hydrochloric Acid

Answer 24

CaCO3(s) + HCl -> CaCl2 + H2O + Co2

Question 25

what is the chemical name for limewater

Answer 25

calcium hydroxide

Question 26

why is the combustion of fossil fuels a concern

Answer 26

releases co2 into the air which may contribute to global warming