Chemical Engineering

Internal Energy and Energy Conversion Concept

Question 1
Marks : +2 | -2
Pass Ratio : 100%
What is the change in internal energy of 1 mole of air ((Cv = 2.1 X 104 J/moleoC), if its temperature changes from 10oC to 5oC?
84 kJ
105 kJ
– 84 kJ
– 105 kJ
Explanation:
Change in internal energy = 1*(2.1 X 104)*(5 – 10) = – 105 kJ.
Question 2
Marks : +2 | -2
Pass Ratio : 100%
What is the change in internal energy of 2 mole of air (Cv = 2.1 X 104 J/moleoC), if its temperature changes from 10oC to 20oC?
420 kJ
540 kJ
840 kJ
1050 kJ
Explanation:
Change in internal energy = 2*(2.1 X 104)*(20 – 10) = 420 kJ.
Question 3
Marks : +2 | -2
Pass Ratio : 100%
What is the change in internal energy for a process which has final and initial states are exactly similar?
Positive
Negative
Zero
Cannot say
Explanation:
Since internal energy is a state function, change in internal energy for the process will be zero.
Question 4
Marks : +2 | -2
Pass Ratio : 100%
A stone has initial potential, kinetic and internal energy 7 J, 10 J and 2x J respectively, if the final kinetic energy, potential energy and internal energy are 5 J, 21 J and x respectively, what is the final internal energy?
2 J
4 J
5 J
9 J
Explanation:
7 + 10 + 2x = 5 + 21 + x, => x = 9 J.
Question 5
Marks : +2 | -2
Pass Ratio : 100%
Total energy of the universe is always ______
Increasing
Decreasing
Constant
Cannot say
Explanation:
According to the law of conservation of energy, the total energy of the universe is always constant.
Question 6
Marks : +2 | -2
Pass Ratio : 100%
A stone has initial potential and kinetic energy as 10 J and 5 J respectively if the final potential energy of the stone is 15 J what is its final kinetic energy?
0
5 J
10 J
15 J
Explanation:
Law of conservation of energy, 10 + 5 = 15 + KE, => KE = 0.
Question 7
Marks : +2 | -2
Pass Ratio : 100%
A stone has initial potential, kinetic and internal energy 4 J, 15 J and 20 J respectively, if the final kinetic energy and potential energy of the stone is 5 J and 10 J respectively, what is the final internal energy?
15 J
20 J
24 J
32 J
Explanation:
Final internal energy = 4 + 15 + 20 – 5 – 10 = 24 J.
Question 8
Marks : +2 | -2
Pass Ratio : 100%
Ratio of change in internal energy of a substance from 15oC to T and from T to 10oC is – 2, what is T?
5oC
15oC
20oC
30oC
Explanation:
– 2 = (T – 15)/(10 – T), => T = 5oC.
Question 9
Marks : +2 | -2
Pass Ratio : 100%
A stone has initial potential and kinetic energy as 5 J and 20 J respectively if the final kinetic energy of the stone is 15 J what is its final potential energy?
0
10 J
15 J
25 J
Explanation:
5 + 20 = 15 + PE, => PE = 10 J.
Question 10
Marks : +2 | -2
Pass Ratio : 100%
Ratio of change in internal energy of a substance from 4oC to T and from T to 10oC is 2, what is T?
5oC
6oC
7oC
8oC
Explanation:
2 = (T – 4)/(10 – T), => T = 8oC.