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# Thermodynamics questions

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1. 5.30 moles of gas, initially at 25 degrees celcius and 5.00 atm pressure, was allowed to expand adiabatically( with no heat exchange between systen and surroundings) against a constant external pressure of 1.50 atm until the initial volume had trebled. The heat capacity of the gas was known to be 37.1 J/ degree celuius mol
Determine the following

1. Inital volume

2. The finial volume

3. w

4. q

5. change in Energy

6. The final temperature of the gas

2. Would it be feasible to make ethanol, C2H5OH, by the following reaction ( under standard conditions and 25 degrees C)

C2H4(g) + H2O(l) --------- C2H5OH(l)

3. Calculate the molar entropy of vaporization of water

change in Hf values (kJ/mol) : C2H4(g) = 52 H2O(l)= -286
H2O(g) = -242 C2H5OH(l) = -278

S Values(J/K mol): C2H4(g) = 220 H2O(l)= 70
C2H5OH(l) = 161

Boiling point H2O is 100 degrees celcuius

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#### Solution Preview

1.1) n = 5.3 moles
Ti = 25 degrees C = (25+273) K = 298K
Using ideal gas equation, PV =nRT
PVi = nRT
Vi = nRT/P
Note that 1 atm = 101,325N/m2
= (5.30 moles x 8.314J/mol/K x 298K) divided by (5 x 101,325)N/m2
= ...

#### Solution Summary

It provides detailed explanations of several thermodynamics questions, such as entropy, change in energy, and work done on gas.

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