Question

A sample of gas absorbs 4000 kJ of heat and surrounding does 2000 J of work on sample. What is the value of \(\Delta U\)?

• A. 2000 kJ
• B. 4002 kJ
• C. 4000 kJ
• D. 6000 kJ

Hint:

The first law of thermodynamics relates heat, work, and change in internal energy. Always be careful to convert units when performing calculations.

Answer 1

The Correct Option is B

Step 1: Understanding the relationship.
The change in internal energy (\(\Delta U\)) is given by the first law of thermodynamics: \[ \Delta U = Q - W \] Where: - \(Q = 4000 \, \text{kJ}\) (heat absorbed by the gas) - \(W = 2000 \, \text{J} = 2 \, \text{kJ}\) (work done by surroundings on the gas)
Step 2: Calculation.
\[ \Delta U = 4000 \, \text{kJ} - 2 \, \text{kJ} = 4002 \, \text{kJ} \]
Step 3: Conclusion.
The correct answer is (B) 4002 kJ.