A quantity of hot water at 100oC is added to 400g of water at 10oC until the temperature of the mixture is 60oC.
Calculate the mass of the hot water added. [Specific heat capacity of water =4200JKg-1 K-1]
A
200g
B
320g
C
400g
D
500g
Verified Correct Answer: D.
Physical Principles & Numerical Solution
Heat lost by hot water = Heat gained by cold water
M x 4200 x (100 - 60 = 0.4 x 4200 x (60 - 10)
4200m x 40 = 0.4 x 4200 x 50
40m = 0.4 x 50
m = \(\frac{0.4 \times 50}{40}\) = 0.5kg
= 500g
Source: Myschool Past Questions Archive (Record #45450)