Chemistry

Question 1

Tests for water

Answer 1

Anhydrous copper(II) sulphate (white) + water <–> hydrated copper(II) sulphate (blue)
Anhydrous cobalt(II) chloride (blue) + water <–> hydrated cobalt(II) chloride (pink)

Question 1

How do we filter and clean water

Answer 1

1) Screen - rid of larger pollutants
2) Coagulant - turns soluble things insoluble / Sedimentary - blow air through the water, trash rises
3) Filter - with sand
4) Carbon - gets rid of odors & bad tastes
5) Chlorine - added to kill bacteria
6) Store in reservoir

Question 2

What is aquifer & microbe?

Answer 2

Aquifer is water found in the ground & microbe is a small organism(s)

Question 3

Name the gas percentages in air

Answer 3

Nitrogen: 78%
Oxygen: 21%
Typically noble gases: 1%
Argon: 0.9%
Carbon dioxide: 0.004%

Question 4

Why do mountaineers carry oxygen cylinders

Answer 4

At higher altitudes, the oxygen content decreases which makes breathing difficult for mountaineers

Question 5

How to find percentage of oxygen

Answer 5

difference in volume/volume at start x 100%

Question 6

Uses of elements in air

Answer 6

Nitrogen: Food preservation
Argon: Lights
Oxygen: Oxygen tanks, making stainless steel

Question 7

How to separate elements in air?

Answer 7

Turn the air into gas by compressing it to heat it, expand to cool it, repeat this until air is liquid

Question 8

How are pollutants created?

Answer 8

Carbon dioxide: respiration in humans, combustion of fossil fuels
Sulfur dioxide: combustion of fossil fuels, volcanos
Methane: cows, sheep, drilling, decomposition of vegetation
Nitrogen oxides: combustion of fuels in vehicles
Carbon monoxide: incomplete combustion of fuels

Question 9

Combustion reaction

Answer 9

Fuel + oxygen = carbon dioxide + water ex. CH4 +2O2 -> CO2 + H2O

Question 10

What compounds/elements does incomplete combustion create?

Answer 10

Carbon & Carbon monoxide

Question 11

Risks of carbon monoxide

Answer 11

Poisonous to humans, exposure to it can bind our haemaglobin with it causing respiratory issues because blood can no longer transport O2

Question 12

What reacts with SO2 and what does it create

Answer 12

CaCO3 + SO2 -> CaSO3 +CO2

Question 13

carbon dioxide leads to

Answer 13

increased global warming, which leads to climate change

Question 14

risk of particulates

Answer 14

increased risk of respiratory problems and cancer

Question 15

risk of methane

Answer 15

increased global warming, which leads to climate change

Question 16

risk of oxides of nitrogen

Answer 16

acid rain and respiratory problems

Question 17

risk of sulfur dioxide

Answer 17

acid rain

Question 18

How to reduce carbon dioxide

Answer 18

planting trees, photosynthesis

Question 19

How to reduce methane

Answer 19

reduction in livestock farming

Question 20

How to reduce nitrogen oxides, carbon dioxide e.t.c

Answer 20

decreasing use of fossil fuels

Question 21

How to reduce emissions of greenhouse gases

Answer 21

increasing use of hydrogen and renewable energy, e.g. wind, solar

Question 22

How to reduce acid rain?

Answer 22

reducing emissions of sulfur dioxide by using low-sulfur fuels and flue gas desulfurisation with calcium oxide

Question 23

Explain how oxides of nitrogen form in car engines and describe their removal by catalytic converters

Answer 23

2CO + 2NO → 2CO2 + N2