Question

100g of hot water at 90c is mixed to 400g of cold water at 10c the equilibrium temperature of the mixture is

Answer 1

Let equilibrium temperature is T.
then, Heat transferred by hot water = ms∆T
= 100g × s × (90 - T)


Heat gained by cold water = m's∆T'
= 400g × s × (T - 10)

Heat transferred by hot water = Heat gained by cold water .

so, 100 × s × (90 - T) = 400 × s × (T - 10)

90 - T = 4(T - 10)

90 - T = 4T - 40

90 + 40 = T + 4T

130 = 5T

T = 26

hence, equilibrium temperature is 26°C

Answer 2

Answer:

26

Explanation:

heat transfner = heat gain

100 *(t -90) =400*9(T-100)

100*90-100t=400t-400*10

9000-100t=400t-4000

9000+4000=400t+100t

500t=13000

t=13000/500

=26