The internal energy change for a system is + 20 Cal and the work
![The internal energy change for a system is + 20 Cal and the work](/img/relate-questions.png)
| The internal energy change for a system is + 20 Cal and the work done is – 200 Cal. Find the heat exchanged between the system and the surrounding.
A. 220 Cal
B. - 220 Cal
C. - 180 Cal
D. + 180 Cal
Please scroll down to see the correct answer and solution guide.
Right Answer is: C
SOLUTION
CONCEPT:
- The first law of thermodynamics is a restatement of the law of conservation of energy. It states that energy cannot be created or destroyed in an isolated system; energy can only be transferred or changed from one form to another.
- When heat energy is supplied to a thermodynamic system or any machine: Two things may occur:
- The internal energy of the System or machine may change.
- The system may do some external work.
According to the first law of Thermodynamics:
ΔQ = ΔW + ΔU
Where ΔQ = Heat supplied to the system, ΔW = work done by the system, and ΔU = change in internal energy of the system
EXPLANATION:
Given that:
ΔW = - 200 Cal and ΔU = + 20 Cal
According to the first law of Thermodynamics:
Heat exchanged (ΔQ) = ΔW + ΔU = - 200 + 20 = - 180 Cal