150 g of water at 60 °C is mixed with 50 g of water at 20 °C. Ignoring heat losses, what is the final temperature?

Answer and explanation

Correct answer: B. 50 °C

  1. Step 1: Heat lost by hot water = heat gained by cold water.
  2. Step 2: T = (150x60 + 50x20) / (150+50) = 50 °C.
Answer
50 °C.
Why not the others: 40 °C: the temperatures were averaged without using the masses. 30 °C: the masses were swapped. 25 °C: the total mass was doubled.

Practise more Calculations in science.

Free questions with an explanation for every one, and full timed Iraqi Third Intermediate Ministerial Exams mock tests.

All Calculations in science questionsTake a mock test

More Calculations in science questions