b Assume that Hokium acts as an ideal gas It is a Circle one monoatomic linear

B assume that hokium acts as an ideal gas it is a

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b) Assume that Hokium acts as an ideal gas. It is a (Circle one): monoatomic linear or nonlinear Δ H o vap Hokium = kJ/mol Show your work to support your answer to b. c) What is the change in entropy for last two steps shown on the graph (vaporization of 1 mole of Hokium @ 250K and heating of the resulting gas to 300 K)? Δ S = J/K 5 9 8 1000 21000 22662.8 200 225 250 275 300 325 0 5000 10000 15000 20000 25000 Temperature(K) heat added (J) Hea1ng curve for Hokium
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CHEM_230_W16_PREP_E1 p 4 6) The graph below shows 0.2 moles of a linear gas taking two different pathways for expanding from point A (5 atm, 0.1L, 298K) to point C (1.5 atm, 0.25L, 223.5K) The first path contains two steps: step 1 (Z 1 ) is a reversible isothermal expansion from A to B followed by step 2 (Z 2 ), cooling from B to C. The second path (X) is an adiabatic expansion from A to C. 1 1.5 2 2.5 3 3.5 4 4.5 5 0.05 0.1 0.15 0.2 0.25 0.3 Pressure(atm) Volume (L) A (5 atm, 0.1 L, 298K) B (2atm, 0.25 L, 298K) C (1.5 atm, 0.25L, 223.5K) step Z 1 step Z 2 path X a) What are the values for the following quantities for each step of each path? Use units of J. Show work for any calculations. Indicate the appropriate sign. Step Z 1 U w q J J J Step Z 2 U w q J J J Path X U w q J J J 18 b) An adiabatic expansion leads to less work done on the surroundings than an isothermal expansion. Circle one: True False 2
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CHEM_230_W16_PREP_E1 p 5 7) 0.0818 mol of copper requires 3612 J to heat it from 298K to 1500K. Copper melts at 1358 K; copper has a Δ H o fus = 13.1 kJ/mol; copper solid has a molar heat capacity of 24.43 J/(K mol). What is the molar heat capacity of liquid copper? 10 C m, liquid Cu = J/(K mol) 13) One mole of an ideal gas is studied at a constant temperature. The volume of the gas at different pressures is measured. Given the plot and equation shown below, at what temperature was the data collected? P (pressure, atm) 1/V (1/volume, 1/L) y = [20.93 (L atm)] (x) T = K 8
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CHEM_230_W16_PREP_E1 p 6 8 6 6 4 10) Assume ideal gases. A manometer is used to monitor the decomposition of N 2 O 5(g). To set up the experiment, one side of the mercury manometer is placed under vacuum. The other side of the manometer is connected to a 10.0 L rigid reaction flask, filled with N 2 O 5, and then heated to 70.0 o C. 2 N 2 O 5 (g) --> O 2 (g) + 4 NO 2 (g) O N O NO 2 is a) The height difference of the mercury in the manometer at 70 o C is 256.7 mm. How many moles of N 2 O 5 are in the flask before decomposition? (Assume no change in density of Hg with temperature.) b) The N 2 O 5 decomposes completely as shown in the balanced chemical equation. Assuming constant temperature what is the new height difference in the mercury in the manometer? mol N 2 O 5(g) = height difference: mm c) What is the partial pressure of oxygen after the decomposition reaction? P O2 : atm d) The decomposition products are cooled from 70 o C to 25 o C. What are the q and w for this process? q = J w = J ( include signs )
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CHEM_230_W16_PREP_E1 p 7 4 6 11) Air is approximately 80% by volume nitrogen and approximately 20% by volume oxygen. An experiment to study air was set up as shown in the figure in the box below. The rigid 200 mL flask on the left is filled with oxygen at STP (0 o C, 1 atm). The rigid 800 mL flask on the right is filled with nitrogen at STP (0 o C, 1 atm). The two flasks are joined by a closed stopcock. Assume ideal gases.
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