Physical Chemistry Ii Question Paper
Physical Chemistry Ii
Course:Bachelor Of Science In Analytical Chemistry
Institution: Jomo Kenyatta University Of Agriculture And Technology question papers
Exam Year:2013
JOMO KENYATTA UNIVERSITY
OF
AGRICULTURE AND TECHNOLOGY.
SCH2201-PHYSICAL CHEMISTY II.
CAT 2
DATE:March 26, 2013
INSTRUCTIONS:ANSWER ALL QUESTIONS.
USEFUL DATA;
O0C=273
R=8.314JK-1mol-1
=0.0821atm K-1mol-1
In x=2.303log x
QUESTION ONE (30 MARKS)
a) Explain how the gas equation PV=nRT has been modified to take account of the behavior of the real gases.(5marks)
b) Explain the significance o f the symbols in the equation PV=nRT and state any two of the gas laws it summarizes.(5marks)
c) Two moles of an ideal gas initially at 270c and one atmosphere are compressed reversibly to half the initial volume. Calculate the value of q, w, ?E and ?H when the process is carried on isothermally. (8marks)
d) A steel bottle contains 20 liters of hydrogen at 270c and a pressure of 50 atm. The gas expands isothermally and reversibly to 100 liters. Calculate:
1) How much heat had to be supplied? (4 marks) 2)The pressure of the hydrogen after expansion. (4 marks) 3)How much work was performed by the gas during expansion .(4 marks)
QUESTION TWO (30MARKS).
1. A)Explain with an example each of the following :
a) An adiabatic process .(2 marks)
b) An isochoric process.(2 marks)
c) Isothermal process.(2 marks)
d) Systems and surroundings.( 2 marks)
e) Closed system and isolated system.( 2 marks)
B)One mole of a diatomic gas at 300k and 5 atm expands to 1 atm. Assuming ideal behavior, calculate w, q, ?E and ?H if the expansion carried out was adiabatic and reversible.
Given CV=20.9JK-1mol-1
Cp=29.9JK-1mol-1 (20 marks)
QUESTION THREE(20 MARKS).
1.Two moles of an ideal monoatomic gas (CV=20.9JK-1mol-1)are heated from 300K to 350K.The volume of the gas changes from 0.02m3 to 0.2m3.Assuming that the heat capacity remains constant in this temperature change for the system, calculate;
i. Entropy change for the system.
ii. Entropy change for the surroundings.
iii. Entropy change for the universe. (20 marks)
QUESTION FOUR (20 MARKS).
A)
i. State the first law of thermodynamics.(2 marks)
ii. Explain what heat is and work in thermodynamics.(2marks)
iii. Explain what internal energy for a system is.(2 marks)
iv. Explain the meaning of a thermodynamic system(2marks)
v. What is a state function ?Give an example(2 marks)
B) Calculate the work done when 2 moles of H2 expands.
i. Isothermally against a constant pressure of atm at 250C from 15 liters to 50 liters.(5 marks)
ii. The gas expands isothermally and reversibly.(5 marks)
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