Chemistry In The Environment Unit Test

Question 1

Percentages of Water

Answer 1

• Earth is 70% water
• 1% of fresh water is in liquid state
• 97% of water is in the oceans
• 2% is in icecaps and glaciers

Question 2

Water Cycle

Answer 2

• Sun energy causes water to evaporate
• As water evaporates it cools into mist, fog and clouds
• When condensed into a liquid, it precipitates
• Then repeats

Question 3

Why does water have a high boiling point and heat capacity?

Answer 3

• Water has strong hydrogen bonds which takes lots of energy to break

Question 4

What ions are commonly responsible for hard water?

Answer 4

Calcium and magnesium

Question 5

Methods to soften water

Answer 5

• Boiling
• ## Sodium Carbonate

Question 6

What is aeration?

Answer 6

• When water is dissolved through agitated water (waterfalls, waves)

Question 7

How can oxygen in water be decreased?

Answer 7

• Waste can lead to increased bacteria populations
• Pollutant-tolerant organisms (bacteria) can cause oxygen to decrease.

Question 8

3 types of contaminants

Answer 8

• Physical (non-dissolvable, oil, waste, soils)
• Chemical (soluble, chemicals, pesticides)
• Biological ( Bacterial and viral, e. coli)

Question 9

What are safe chlorine levels in water?

Answer 9

0.1 - 0.4 ppm
Above 1 ppm you can taste it

Question 10

What can hard water cause (health-wise)

Answer 10

• Kidney Stones
• Pipe and dishwasher scaling
• Problems for industry

Question 11

What is a good standard for alkalinity?

Answer 11

Above 80 ppm

Question 12

Ph in water

Answer 12

• 7 is neutral, 6-9 is considered safe
• 1-6 is acidic
• 9-14 is basic

Question 13

What are the 2 types of water hardness?

Answer 13

Temporary - can remove ions by boiling
Permanent - can’t remove ions by boiling

Question 14

What can water quality kits test for

Answer 14

• Nitrate
• Phosphate
• Hardness
• Chlorine
• Dissolved O2
• CO2
• Silica
• Iron

Question 15

Testing for ions in water

Answer 15

Positive test - colour change or precipitate, indicates an ion is resent
Negative test - does not mean an ion is absent

Question 16

Qualities of acids

Answer 16

• Ph above 7
• Burns skin
• Sour taste
• Water soluble
• Turns blue litmus red
• Neutralizes bases
• Produces H2 when reacting with metals

Question 17

Qualities of Bases

Answer 17

• Ph below 7
• Slippery on skin
• Bitter taste
• Water soluble
• Turns red litmus blue
• Neutralizes acids

Question 18

Differentiate between electrolytes and non-electrolytes

Answer 18

Electrolytes are conductive, compounds separate into ions
Non-electrolytes don’t conduct, don’t dissociate

Question 19

How can acids be strong or weak

Answer 19

Strength depends on how many molecules ionize in water, more ionization = stronger acid

Question 20

How is each unit on the Ph scale represented

Answer 20

Ten fold
An increase in one is 10

Question 21

Dilution

Answer 21

Many products and acids are diluted
Dilution causes pH values to increase

Question 22

Reactions of Acids and Bases

Answer 22

• Combustion reactions produce oxides
• Oxides form with water to form acid rain
• Acids and bases combine in neutralization reactions to produce water and a salt compound
• Strong acids and bases produce heat (explosion)

Question 23

What pH does acid rain have?

Answer 23

5.6 pH, slightly acidic due to dilute carbonic acid

Question 24

What compounds contribute to acid rain?

Answer 24

Carbon dioxide, Sulphur oxide nitrogen oxides

Question 25

How is carbon dioxide produced?

Answer 25

- Respiration - Volcanic eruptions - Forest fires - Burning of fossil fuels and wood

Question 26

How are nitrogen oxides produced?

Answer 26

- Lightning strikes - Plant decay - Burning of fossil fuels, 40% - Geothermal generation, 25% - Industrial practices, 35%

Question 27

How do compounds form acid rain?

Answer 27

In gaseous form, these compounds can be carried long distances which gives them time to form acids with water vapour.

Question 28

How can acid rain be neutralized in a lake?

Answer 28

Limestone bedrock

Question 29

How are sulphur oxides produced?

Answer 29

- Combustion of coal and oil

Question 30

Titrations

Answer 30

- The acid is called an analyte - The base is called the titrant

Question 31

How does respiration affect the atmosphere?

Answer 31

You breathe out gases that affect the atmosphere

Question 32

What happens to a particle as speed increases?

Answer 32

Energy increases, then heat increases

Question 33

Boyle's law states

Answer 33

As the pressure of a gas increases the volume decreases, as long as the temperature and amount are constant

Question 34

Charles's law states

Answer 34

As the temperature of a gas increases, the volume increases, as long as pressure and amount are constant

Question 35

What is one Kelvin?

Answer 35

273K