Topic 2 Environmental Chemistry

Question 1

What element found in PCB’s causes the thinning of the ozone layer?

Answer 1

Chlorine

Question 2

How is ppm calculated?

Example: 0.001/1000

Answer 2

Ex

0. 001/1000 = X/1000000
1. 001/1000 x 1000000 = X/1000000 x 1000000

X=1

Question 3

Name the 6 chemical factors that effect organisms

Answer 3

> Dissolved Oxygen

> Acidity

> Heavy Metals

> Plant Nutrients

> Pesticides

> Salts

Question 4

What factors influence the level of dissolved oxygen?

Answer 4

> Temperature

> Turbulence (wind or speed of moving water)

> Amount of photosynthesis of plants or algae

> Number of organisms using up the oxygen

Question 5

Which lake has the most diverse ecosystem?

Lake pH Dissolved Phosphorus
Oxygen

A). 1.3 1.5 Low
B). 6.2 6.5 High
C). 7.1 7.0 Low
D). 9.8 10.0 High

Answer 5

C) pH closest to 7 is best and lower phosphorus levels are better to prevent plant decay

Question 6

What are heavy metals

Answer 6

Metals that have a density of 5g/cm3 (5 times heavier than water)
They are also toxic to many organisms in large doses.

ex. Mercury,lead,cadmium,zinc,
copper and nickel

Question 7

What is Sulfur Dioxide? What is a main source of this?

Answer 7

A major air pollutant that forms from smog and acid rain. It can affect your respiratory system and irritate your eyes. Major sources include the oil and gas industry

Question 8

What are scrubbers

Answer 8

Scrubbers are chemicals that convert harmful pollutants into a useful product

Ex. Limestone

SO2+Water+Limestone+Oxygen-> Gypsum+CO2

Question 9

What are nitrogen oxides? What is a main source of this?

Answer 9

Nitrogen oxides are major air pollutants that affect your respiratory system. They are a mixture of various oxides of nitrogen. The main source is from the combustion in vehicles and industrial sites

Question 10

Is ozone harmful to humans?

Answer 10

It depends on where it is located. If it is on the ground, Yes it affects our breathing. If it is in the atmosphere, No it protects us from the sun’s UV rays. Ozone is made of three oxygen atoms

Question 11

What is carbon monoxide and why is it harmful to humans?

Answer 11

Carbon monoxide is an odourless, colourless gas formed from motor vehicles and human activity. Carbon monoxide thins the blood from oxygen therefore people have difficulty breathing

Question 12

Which of these times and locations can be affected by spring acid shock?

A) April in Halifax
B) September in Moscow
C) July in New York
D) April in Los Angeles

Answer 12

A) This is because spring acid shock can only happen during spring and in place that get snow

Question 13

What is toxicity?

Answer 13

How poisonous a substance is

Question 14

Explain the LD50 for 3000mg/kg when given to rats

Answer 14

50% of the rats given the LD50 dose survive

Survive instead of died because the population can have various sizes and ages.

Question 15

Which LD50 dose is more lethal

0.007

OR

0.0007

Answer 15

0.0007 because a smaller dose is required for the test subject to die off. This is because this dose is more lethal

Question 16

What is the enhanced greenhouse effect?

Answer 16

The greater concentration of gases trapping more heat. This increases the temperature around the world

Question 17

Why is global warming happening?

Answer 17

The thinning of the ozone layer lets more UV rays through and cause an increase in temperature around the world

Question 18

What are chlorofluorocarbons and why are they dangerous?

Answer 18

Chlorofluorocarbons (CFC’s) are chemicals found in some products. The chlorine in CFC’s contributes to the thinning of the ozone layer.

Question 19

If 2mL of food colouring is added to 998mL of water, what is the concentration of the food colouring?

Answer 19

2/1000 = X/1000000

2 x 1000000 = x/1000000 x 1000000

X=2000