# chemistry

posted by
**Anonymous**
.

When 86.7 g of water at a temperature of 73 °C is mixed with an unknown mass of water at a temperature of 22.3 °C the final temperature of the resulting mixture is 61.7 °C. What was the mass of the second sample of water?

(Specific heat of water 4.184 J·g-1·°C-1)