U1_M1_HW-key

# U1_M1_HW-key - Module 1 Investigating other Planets The...

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Module 1 Investigating other Planets The analysis of the atmosphere of other planets in our Solar System is of central importance for understanding not only how our planet originated but for exploring the possibility of life beyond Earth. The following table summarizes relevant information for the atmosphere of Venus, Earth, and Mars: Venus Earth Mars Distance from Sun in Astronomical Units (AU) 0.723 1.00 1.50 Average surface Temperature 460 o C (day) 460 o C (night) 20 o C (day) 10 o C(night) -5 o C (day) -85 o C(night) Extreme temperatures 500 o C (highest ) 400 o C (lowest) 58 o C (highest) -88 o C (lowest) 27 o C (highest) -143 o C (lowest) Air density at ground level 65 kg/m 3 1.2 kg/m 3 ~0.020 kg/m 3 Atmospheric pressure at ground level 92 atm 1.0 atm 0.0059 atm Atmosphere composition (Main components) 96.5% CO 2 3.5 % N 2 0.015% SO 2 0.002% H 2 O 78% N 2 21% O 2 ~1% H 2 O 0.035% CO 2 95.3 % CO 2 2.7 % N 2 0.13 % O 2 0.03 % H 2 O As you can see, the atmospheric conditions in these three planets are very different. This implies that the same substances may exist in different states of matter from one planet to another. The phase behavior of a substance in a given planet can be predicted using their respective phase diagrams. In particular, in this page we present the phase diagram of water (H 2 O and carbon dioxide (CO 2 ). H 2 O CO 2 Important Notes: 1 atm = 101.325 kPa T(K) = T( o C) + 273.15 The pressure in these diagrams is represented using a logarithimic scale.

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Answer the following questions based on the information provided and your own knowledge of the phase behavior of chemical substances. You may also need to do some basic research to find relevant phase behavior data for other substances present in these planets. 1. What is the state of matter of H 2 O and CO 2 at day and night in each of these planets? Justify your answer by indicating on the phase diagrams the state of the substance in each of the planets. Venus Earth Mars Day gas (H 2 O), scf (CO 2 ) Liquid (H 2 O), gas (CO 2 ) solid (H 2 O), gas (CO 2 ) Night gas (H 2 O), scf (CO 2 ) Liquid (H 2 O), gas (CO 2 ) solid (H 2 O), gas (CO 2 ) 2. Would it be possible to find solid CO 2 (dry ice) in any of these planets? Justify your answer. For Venus, no. For Mars and Earth, yes but only in the extreme case low temperatures (for Earth it would have to be -88 with an atmospheric pressure of 1atm. 3. Would it be possible to find liquid N 2 in any of these planets? Justify your answer. No. You would have to get to a very cold temperature (around -190) and none of the planets do this. 4. The United States and Soviet Union have sent many spacecraft to Venus. Some flew by the planet, some orbited it, and some descended through the atmosphere. Imagine that you were able to get a sample of Venus’ atmosphere, how would you propose to separate its main components? In which order would you be able to separate them? Write a detailed description of what you propose to do
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## This note was uploaded on 04/09/2009 for the course CHEM 151 taught by Professor Staff during the Fall '08 term at Arizona.

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U1_M1_HW-key - Module 1 Investigating other Planets The...

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