Amity University 2006 Diploma Information Technology iit jee with answers - Question Paper

Passage one
When heat is added to a gas, the temperature increases and the gas expands. If the gas is in a rigid container, then the quantity remains constant and the pressure increases. If the gas in in a container that can expand (for example a cylinder with a vertical piston), then the pressure remains constant but the quantity expands.
The amount of energy needed to increase the temperature of 1 mole of gas is called the specific heat; there is a specific heat for constant pressure (Cp) and a specific heat for constant quantity ((Cv).
In formula form, this is written:


Delta Q is the energy needed to raise the temperature of the gas by a certain amount (delta T). The specific heats for a few gases, including monoatomic gases such as helium and argon, and diatomic gases such as nitrogen and oxygen, are provided in the table beneath.
Specific Heat of a few Gases
Gas Cv Cp Cp-Cv
Helium(H) 3.00 4.98 1.98
Argon(A) 3.00 5.00 2.00
Nitrogen(N2) 4.96 6.95 1.99
Oxygen(O2) 4.96 6.95 1.99
Carbon Monoxide(CO) 4.93 6.95 2.02
Carbon Dioxide(CO2) 6.74 8.75 2.01
Methane(CH2) 6.48 8.49 2.01

Note: All quanties are in calories(Kelvin*mole)
Q. one Let X be the energy needed to raise the temperature of five moles of nitrogen held at constant pressure by 1 degree. Let Y be the energy needed to raise five moles of carbon monoxide by 1 degree with the pressure held constant. What is the ratio X:Y?
A. 5:7
B. 1:1
C. 7:5
D. 7:9
Answer: B
Discription: There is no need to do any computations here. If you put X on top of Y, you will see that it decreases to the ratio of Cp for nitrogen over Cp for carbon monoxide. And since both gases have the identical Cp, the ratio is simply 1:1.
Q. two The difference Cp - Cv is a constant. This constant is often called R, the universal gas constant. Which of the subsequent is actual provided the data?
A. For a monoatomic gas, Cp = 3/2 R
B. For a diatomic gas, Cp = 3/2 R
C. For a monoatomic gas, Cv = 3/2 R
D. For a diatomic gas, Cv = 3/2 R
Answer: C
Discription: Helium and argon are monoatomic gases, and we can see that Cv = 3/2 *R = (3/2)*2 = 3.
Q. three How much energy would be needed to heat 2 moles of methane by 1 degree if the gas is kept at constant volume?
A. 6.5 calories
B. 8.5 calories
C. 11 calories
D. 13 calories
Answer: D
Description: The definition of Cv is the amount of energy needed to heat 1 mole of a gas by 1 degree. Therefore, to heat 2 moles of methane by 1 degree will require 2*6.5 = 13 calories.
Q. four Which of the subsequent is a possible explanation for the fact that Cp is always greater than Cv?
A. Some of the energy is used to expand the container in order to maintain constant pressure.
B. A rigid container does not conduct heat as well as 1 that can change shape.

Earning:   Approval pending.