A 1.00kg piece of aluminum metal at 90 degrees Celsiusis placed in 4 L (=4.00kg) of water at 25°C determine the final temperature

From the basic "heat lost by hot object=heat gained by colder object" principle, we have

m1c1ΔT1=m2c2ΔT2

where m1 = 1kg

m2=4kg

c1=900J/kg k

c2=4200J/kg k

With this information at hand we have

m1c1 (90-T) = m2c2 (T-25)

after substituting the given values we can find that

T=28.3^{0}c