Question 41
Change of State and VapoursAll the heat generated in a 5 ohm resistor by 2 A flowing for 30 seconds is used to evaporate 5 g of a liquid at its boiling point. Which of the following is the correct value of the specific latent heat of the liquid?
- A.120 J
- B.60 J g−1
- C.120 J g−1
- D.1500 J
- E.1500 J g−1
Show the answer and explanation
Answer: C (120 J g−1)
Explanation
Heat = I²Rt = 2² × 5 × 30 = 600 J. Latent heat = 600 J ÷ 5 g = 120 J g−1.