st
1
Law of
Thermodynamics
More Problems

A.
B.
C.
D.
In the equation Q=U+W, the
quantities Q and W represent
The heat released by the system
and the work done by the system.
The heat released by the system
and the work done on the system.
The heat supplied to the system
and the work done by the system.
The heat supplied to the system
and the work done on the system.

A.
B.
C.
D.
25 kJ of work is done on the system
consisting of 3 kg of water by
stirring it with a paddle wheel.
During this time, 62.7 kJ of heat is
removed. What is the change in
internal energy of the system?
-87.7 kJ
-37.7 kJ
+37.7 kJ
+87.7 kJ

A.
B.
C.
D.
300 J of work is done on the gas
during compression. In the process,
400 J of energy leaves the gas by
heat. What is the change in the
internal energy of the gas?
-700 J
-100 J
+100 J
+700 J

A.
B.
C.
D.
A thermodynamic system
undergoes a process in which its
internal energy decreases by 500 J.
At the same time, 220 J of work is
done on the system. Find the heat
involved in the process.
-720 J
-280 J
+280 J
+720 J

A.
B.
C.
D.
If 400 kJ is added to a gas that
expands and does 800 kJ of
work, what is the change in the
internal energy of the gas?
-1200 kJ
-400 kJ
+400 kJ
+1200 kJ

A.
B.
C.
D.
A diatomic gas does 300 J of
work and also absorbs 600 J
of heat. What is the change in
the internal energy of the gas?
-900 J
-300 J
+300 J
+900 J

A.
B.
C.
D.
Consider that 200 J of work is done
on a system and 70 J of heat is
extracted from the system as heat.
What is the change in internal
energy of the system?
-270 J
-130 J
+130 J
+270 J

A.
B.
C.
D.
When 20 J of heat is absorbed
by a gas, the system performs
30 J of work. What is the
change in the internal energy
of the gas?
-50 J
-10 J
+10 J
+50 J

A.
B.
C.
D.
During a certain thermodynamic
process, a sample of gas expands
and cools, reducing its internal
energy by 3000 J. During which
500 J of heat is added. How much
work is done during this process?
-3500 J
-2500 J
+2500 J
+3500 J

A.
B.
C.
D.
While a gas does 200 J of
work, its internal energy
increases by 700 J. How much
heat is involved in the
process?
-900 J
-500 J
+500 J
+900 J