Without considering the containing vessel, what mass of boiled water can raise the temperature of 8 kg of water from 25^\circC to 60^\circC when mixed in a heat-proof container?
A
10kg
B
7kg
C
5kg
D
6kg
Verified Correct Answer: B.
Physical Principles & Numerical Solution
Answer: B. 7kg
(Heat balance: m \times 4200 \times (100 - 60) = 8 \times 4200 \times (60-25);
m = \(\frac{(8 \times 35)}{40}\) = 7 kg.)
Source: Myschool Past Questions Archive (Record #74367)