Air and Water

Air and Water
1. Explain fully with the aid of diagrams why the tropopause is encountered at its lowest height near to the poles. (2 marks)

2. Use Boyle’s Law to solve the following. Show working. (4 marks)

12 litres of a gas at standard temperature and pressure is compressed to 3 litres. What is the new pressure of the gas?

3. Use Charles Law to solve the following. Show working. (4 marks)

A plastic bottle is flexible enough that the volume of the bottle can change even without opening it. If you have an empty bottle (volume 1.5 litres) at a temperature of 21 degrees Celsius, what will the new volume be if you put it in your fridge for a few hours (4 degrees Celsius)?

4. Use the Combined Gas Law to answer the following. Show working. (6 marks)

If I initially have a gas at a pressure of 15 atm, at a volume of 33 litres and a temperature of 3 degrees Celsius and then I raise the pressure to 18 atm and increase the temperature to 55 degrees Celsius, what is the new volume of the gas?

5. Use the Ideal Gas Equation to solve the following. Show working. (6 marks)

If I have 22 moles of gas at a pressure of 0.39 atm and at a temperature of 36 degrees Celsius what is the volume of the container that the gas is in?

6. What common atmospheric gas absorbs light with a wavelength of 1.4 micrometres? Why exactly does that gas let light with other wavelengths pass through? (4 marks)

7. Explain using the appropriate equation why the sun is 20 times hotter than the Earth yet emits 160,000 times more energy per unit area. (5 marks)

8. What is the maximum wavelength of emission of a blackbody with a surface temperature of 1000 degrees Celsius? Show workings. (5 marks)

9. Define the term ‘solar constant’ and explain why it may vary over time. (6 marks
Figure 1 The Keeling Curve 1960-1996

10. Account for the trends and variability in atmospheric carbon dioxide concentration (measured at Mauna Loa) as shown by this segment of the Keeling Curve. Find out what the concentration is now and determine if the growth trend since 1996 has been stable (8 marks)

11. Miranda, the innermost of the Uranian moons that were known prior to the Voyager 2 flyby, has a surface temperature of about 86K. At what wavelength does the peak blackbody emission from Miranda occur? Repeat the calculation for Neptune’s moon Triton, the coldest known body in the solar system at 38K. (6 marks)

Temperature (degrees C) Saturation Mixing
Ratio (g/kg)
-40
-30
-20
-10
0
5
10
15
20
25
30
35
40
0.10
0.30
0.75
2.00
3.50
5.00
7.00
10.00
14.00
20.00
26.50
35.00
47.00
Table 1
12. Use table 1 to answer the following questions,

(a) If a parcel of air at 25 degrees Celsius contains 10 grams of water vapour per kilogram of air, what is its relative humidity?
(b) If a parcel of air 35 degrees Celsius contains 5 grams of water vapour per kilogram of air, what is its relative humidity?
(c) If a parcel of air 15 degrees Celsius contains 5 grams of water vapour per kilogram of air, what is its relative humidity?
(d) If the temperature of the parcel of air in part (c) dropped to 5 degrees Celsius, how would its relative humidity change?
(e) If air with a temperature of 10 degrees Celsius contains 7 grams of water vapour what is its dewpoint?
(f) If air with a temperature of 20 degrees Celsius has a relative humidity of 50% what is the mixing ratio? (6 marks)

13. Fully explain why the pattern of pressure over the British Isles in figure 2 would lead to cloudless conditions however it would be very windy in southern Scandinavia (4 marks)

Figure 2 Synoptic Chart mystery date

14. In one sentence define the following terms (8 marks)

(a) Polar vortex
(b) Chlorine reservoir
(c) PSC
(d) Photodissociation

 

Module Learning Outcomes and Key Skills

The following Learning Outcomes and Key Skills will be assessed:

a) demonstrate a knowledge and understanding of the major physicochemical principles operating in the atmosphere,

b) show an awareness of personal learning strategies,

c) present a clearly structured summary or synthesis,

d) apply basic concept, principles and techniques to standard problems

e) identify the main features of a problem
Assessment and Grading Criteria

Your work will be assessed according to the following criteria,
GRADE
A Excellent. Accurate and precisely worded answers. Appropriate explanations. Clear understanding demonstrated.
B Very Good. Answers are appropriately explained in a good level of detail. One or two errors but generally a good understanding of the problems.
C Good. A competent set of answers that could be developed further. Several errors and omissions.
D Reasonable. Provides a certain indication that some understanding has been achieved but there are several significant inaccuracies and omissions. Further work is needed.
FAIL Fails to meet minimal standards. Major deficiencies. Incorrect answers. Lack of understanding. Omissions
Notification of Grades
Results will be notified to you within three weeks of the submission deadline date. Please note that all grades are provisional until approved by the Board of Examiners.

Submission of Assignment
• Submit one copy together with the signed Student Declaration Form to the Student Assessment Office by the specified deadline date (see above).
• If you are unable to meet the deadline date for any reason you are strongly urged to contact the tutor concerned. (Nb.Note that assignments handed in after the Deadline Date may be penalised.) See the CAF Student Handbook for policies on Extension to Deadlines, Mitigating Circumstances, and for Failure and Re-Assessment.
• Do not staple your work – use paperclips only
• If you use a folder do not put individual pages in separate wallets

Very Important:

• For further advice on submitting assignments see Module Guide.

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