1 CHEM 241
Chemistry Department, Science Faculty of girls King AbdulAziz University
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(1) A piston cylinder contains air at 600 kPa, 290 K and a volume of 0.01 m3. A constant pressure process gives 54 kJ of work out. Find the final volume and temperature of the air.
(2) Calculate the PV work done in joules when a sphere of water 1.00 m (1m = 10-6 m) in diameter freezes to ice at 0 oC and 1 atm?
(3) Calculate the work (in Joule) done on the system for each of the following examples.
(i) A mass of 80 kg is lifted 310 m. The system is the mass.
(ii) The volume change of the system from 24L to 1L under a constant pressure of 1000 mmHg?
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(4) Two moles of ideal gas are heated at constant pressure from T= 27 oC to 107 oC.
(A) Draw a P-V diagram for this process.
(B) Calculate the work done by the gas.
(5) Consider an isobaric compression of 0.450 mol of an ideal gas from 22.4 L and 1.00 atm to 10.5 L.
Given that Cp for the gas is 5/2R, calculate T , q, w, U and H .
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(6) A kettle containing 1 kg of boiling water is heated until evaporation is complete. Calculate W , q, E and H ?
(7) The constant-pressure heat capacity of helium is 20.79 J.K-1mol-1. How much heat is required to raise the temperature of a sample of 1 mole by 10 K at 25 oC (a) when it is in a constant volume vessel at a pressure of 10 atm, (b) when it is in a vessel fitted with a piston subjected to a constant external pressure of 10 atm? How much work is done in each case?
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(8) Four moles of Ar are taken from state (a) to state (b) by the process shown in the P-V diagram. Assuming the gas may be treated as ideal. What is the heat flow ( q ) during this process? Does the heat enter or leave the gas?
Problem (II-12).
(9) Tow moles of Ne start at pressure of 1.2 atm and volume 30 L. The gas is then compressed adiabatically to 1/3 of this volume. Assume that the gas may be treated as ideal. What is the change in the internal energy of the gas? Does the internal energy increase or decrease? Does the temperature of the gas decrease or increase during this process? Explain.
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(10) A-A body of air which occupies 1000 cm3 at 30 oC and 76 cmHg, expands isothermally and reversibly to a volume 2000 cm3. What is (a) the final pressure? (b) the work done? (c) the heat absorbed?
B- The air then expands adiabatically to a volume 3000 cm3. What is (a) the final pressure? (b) the final temperature? (c) the work done? Assumes that the air is an ideal gas with heat capacities:
CV = (5/2)R and CP = (7/2)R
