Unit 10 - Chemistry of the environment

Question 1

steps to treating water? what do they do? (8 steps)

Answer 1

1) screen - filters big particles such as trash
2) coagulant is added - small soluble particles stick together and become insoluble
3) Sedimentation - air is blown through flotation tank to make coagulated particles float to the top (skimmed off)
4) filtration through sand
5) further filtration - charcoal or more sand to get rid of bad smell and taste
6) chlorine - kills bacterias and other microbes
7) fluride - help fight tooth decay
8) water is pumped to storage resevoir - to be pumped into homes

Question 2

2 water tests? positive result?

Answer 2

anhydrous copper sulphate
-white powder –> blue

anhydrous cobalt chloride
-blue –> pink

Question 3

air components?

Answer 3

78% nitrogen
21% oxygen
1% argon + other gases

Question 4

6 common pollutants? symbols?

Answer 4

-carbon dioxide (CO2)
-sulfur dioxide (SO2)
-carbon (C)
-nitrogen monoxide (NO)
-carbon monoxide (CO)
-nitrogen dioxide (NO2)

Question 5

5 air pollution sources?

Answer 5

-combustion of fossil fuels
–> transportation
–> electricity
–> energy (for industry)

-open waste burning (plastic)

-agriculture
–> animal’s burps
–> makes methane (CH4)

-Burning of fossil fuels
–> makes CO2, CO, C, SO2, NO2

-Decomposition
–> makes methane (CH4)

Question 6

complete combustion formula?

Answer 6

CH4 + O2 –> CO2 + H2O

Question 7

incomplete combustion formula?

Answer 7

CH4 –> CO + C

Question 8

how is nitrogen dioxide made?

Answer 8

in internal combustion engines (car engines) as it has high temperature and high pressure and has both nitrogen and oxygen (in air)

Question 9

effects of solid pollutants?

Answer 9

-dust
-carbon
-stops sunlight
–> no vitamin D
–> plants can’t photosynthesis, they die, everything dies

Question 10

effect of acid rain?

Answer 10

-bridges collapse
-lungs have water which react with sulfur dioxide, makes sulfuric acid and melts lungs
-plants and animals get damaged

Question 11

percentage of oxygen formula?

Answer 11

(difference in volume / volume at start) x 100

Question 12

source of carbon dioxide?

Answer 12

-burning of fossil fuels
-respiration
-complete combustion of carbon - containing fuels
-sodium carbonate + HCl
-Thermal decomposition
–> breaking apart something because of acid or heat (1 reactant)

Question 13

carbon and carbon monoxide source?

Answer 13

incomplete combustion of carbon containing fuels

Question 14

sulphur dioxide source?

Answer 14

combustion of fossil fuels (that contain sulfur compounds)

Question 15

nitrogen oxides source?

Answer 15

internal combustion (car engines)

Question 16

methane source?

Answer 16

-waste gases from animal digestion
-decomposition of vegetation

Question 17

fully combusted carbon forms?

Answer 17

CO2

Question 18

fully combusted hydrogen forms?

Answer 18

H2O

Question 19

carbon monoxide + oxygen?

Answer 19

carbon dioxide

Question 20

hydrocarbon + oxygen?

Answer 20

carbon dioxide + water

Question 21

nitrogen monoxide + carbon monoxide?

Answer 21

nitrogen + carbon dioxide

Question 22

ways to reduce effects of climate change [4]

Answer 22

-plant trees
-decrease livestock farming
-decrease fossil fuels burning (use)
-increase use of hydrogen and renewable energy
–> solar panels
–> windmills
–> tidal (waves)
–> geothermal
–> hydrogen powered
–> nuclear
–> hydro-electric power

Question 23

Concentration = ?

Answer 23

number of moles / volume

Question 24

number of moles = ?

Answer 24

volume x concentration

Question 25

what does sunlight do?

Answer 25

-heat up earth -re-emitted (go back) -straight back through cloud -bounces off clouds --> increases global temperature --> greenhouse effect

Question 26

why is distilled water used in practicals?

Answer 26

contains fewer chemical impurities than tap water

Question 27

effect of carbon dioxide?

Answer 27

-higher levels = increased global warming (blanket forms) --> climate change ( -its a greenhouse gas --> greenhouse effect

Question 28

effect of carbon monoxide

Answer 28

toxic gas

Question 29

effect of particulates

Answer 29

increased risk of respiratory problems + cancer

Question 30

effect of methane

Answer 30

-higher levels = increased global warming (blanket forms) --> climate change -it's a greenhouse gas --> greenhouse effect

Question 31

effect of oxides of nitrogen

Answer 31

respiratory problems acid rain -water + nitrogen dioxide --> nitric acid

Question 32

effect of sulfur dioxide

Answer 32

acid rain -water + sulfur dioxide --> sulfuric acid

Question 33

climate change examples

Answer 33

extreme weathers -droughts -tornados -forest fires -ice melts -water level rises -floods -->affects health

Question 34

reduce acid rain by?

Answer 34

-reduce emission of sulfur dioxide --> use low sulfur fuels --> use flue gas desulfurisation with calcium oxide at coal burning power stations

Question 35

how do greenhouse gases cause global warming?

Answer 35

-absorption, reflection, emission of thermal energy -reduces thermal energy loss to space

Question 36

removal of nitrogen oxides by catalytic converters?

Answer 36

2CO + 2NO --> 2CO2 + N2