Chemistry 12HL
Unit 1
Environmental Chemistry
Summer Assignment Review
Names:
Work in groups of 2 or 3 and submit ONE copy at the end of class.
1. On a blank A4 piece of paper, draw a mind map to summarize your understanding of the
five main types of air pollutants. Include chemical names AND formulas, and any
relevant chemical equations. Include connections to other topics where appropriate (e.g.
other topics in Environmental Chemistry, or perhaps to anything else you have learned in
Chemistry.)
2. Comment on these chemical equations or partial equations relating to environmental
chemistry. Consider these types of questions: Where/when does this reaction occur?
Why is it important? Where do the reactants come from? What are the products (if they
are not given)? What are the effects of the products? Is the equation balanced?
a) CaCO3(s) + H2SO4(aq) à
CaSO4(aq) + H2O(l) + CO2(g)
b) C2H5Cl(g) à C2H5(g) + Cl•(g)
c) N2(g) + O2(g) à
d) SO2(g) + H2O(l) à
Chemistry 12HL
3. a) Describe the different roles of ultraviolet radiation and infrared radiation in
environmental problems.
b) Discuss how and why different wavelengths of uv radiation are used in different
processes.
4. Outline the processes in multistage distillation and reverse osmosis.
Discuss the advantages and disadvantages of each method.
Unit 1
Chemistry 12HL
Unit 1
5. Give the formula, name and use of the product of:
a) aerobic decomposition of phosphorus
b) anaerobic decomposition of hydrogen
c) aerobic decomposition of carbon
d) anaerobic decomposition of nitrogen
6. Plasterboard is made from gypsum, CaSO4.2H2O. Explain with the relevant equations
how gypsum can be obtained from pollutant sulfur dioxide gas through a process known
as alkaline scrubbing.
7. Two different alternatives to the use of chlorofluorocarbons(CFCs) are hydrocarbons (HCs)
and hydrofluorocarbons (HFCs).
a) Explain why they are not ozone-depleting gases
b) Give two disadvantages for each of the alternatives when they are used to replace
CFCs.
Chemistry 12HL
Unit 1
7. WITHOUT looking at your notes, outline the processes used in the recycling of
a) aluminum
b) your choice – glass or plastic
8. What are the characteristics and sources of high level vs low level radioactive waste?
9. May 2010 past paper question
Disposal of radioactive waste is a major ecological concern.
a)
State one source of low-level radioactive waste and one source of high-level radioactive
waste. [2]
b)
Consider the following types of radioactive waste. Identify which method can be used for
the disposal of radioactive wastes A, B and C.
Chemistry 12HL
i)
Unit 1
Vitrification followed by long-term underground storage [1]
type: ____
ii)
reason:
Storage in a non-shielded container for two months followed by the disposal
as normal (non-radioactive) waste [1]
type: ____
iii)
reason:
Ion-exchange and adsorption on iron(II) hydroxide, storage in a shielded
container for 50 years, then mixing with concrete and shallow land burial
type: ____
10.
[1]
reason:
The Winkler method is used to find the dissolved oxygen content of a water sample.
3
100 cm of water was taken from a river and analysed using this method. The
reactions taking place are summarized below.
2+
–
Step 1
2Mn (aq) + 4 OH (aq) + O2(aq) → 2 MnO2(s) + 2 H2O(l)
Step 2
MnO2(s) + 2 I (aq) + 4 H (aq) → Mn (aq) + I2(aq)+ 2 H2O(l)
Step 3
2 S2O3 (aq) + I2(aq) → S4O6 (aq) + 2 I (aq)
–
2-
+
2+
2-
–
–
a) 0.0008 moles of I were formed in step 3. Calculate the amount, in moles,
of oxygen, O2, dissolved in water.
b)
3
-3
In another test, you are told that 20.0 cm of 0.00025 mol dm sodium
thiosulfate (Na2S2O3) is needed in step 3 to react with all the I2 that formed in
step ii.
2–
i)
Calculate the amount, in moles, of S2O3
that reacts with the I2.
ii)
Calculate the amount, in moles, of I2 present in the sample.
iii)
Calculate the amount, in moles, of O2, present in the sample.
iv)
Calculate the concentration of O2 present in the sample.