Question

A bucket contains 10 kg of hot water at 70°C. The water is cooled for bathing by mixing
20 kg of water at 10 degree celcius . Calculate the final temperature of the mixture. INeglect the heat
absorbed by the bucket).​

Answer 1

Answer:

m (hot water) =10kg,

T (hot water) =70oC

m (cold water) =20kg

T (cold water) =20oC,T(final)=?

Using the formula Q=mCΔt

We get heat lost by hot water

=10×C×(70−Tf)

Where Tf is the final temperature

Heat gained by cold water

=20×C×(Tf−20)

Using the principle of calorimetry

Heat lost = Heat gained

We get 10×C×(70−Tf)

=20×C×(Tf−20)

∴700−10Tf=20Tf−400

or 30Tf=1100∴Tf=36.67oC.