200g of water at 90°C is mixed with 100g of water at 30°C. What is the final temperature?
- 50oC
- 60oC
-
70oC
- 80oC
The correct answer is: C
Explanation
Heat lost = heat gained
200 x c x (90 - \(\theta\))= 100\(\times\) c \(\times\) (\(\theta - 30\))
Dividing through by 100c, we have
2(\(90 - \theta\)) = (\(\theta - 30\))
simplifying, we have
\(\theta\) = 70°