Question

Suppose that 0.84 g of water at 25 °C condenses on the surface of a 51 g block of aluminum that is initially at 25 °C. If the heat released during condensation goes only toward heating the metal, what is the final temperature (in °C) of the metal block? (The specific heat capacity of aluminum is 0.903 J/g °C; enthalpy of vaporization of water is 44.0kJ/mol at at 25 °C. Also, remember that the heat reuired to increase the temperature of a substance by ΔT is given as Q=mCsΔT, where m is the mass of the substance, and Cs its specific heat).

Answer 1

The final temperature of the metal block : t=69.5 °C

Further explanation

Given

0.84 g water

Aluminum block = 51 g

Required

The final temperature

Solution

Enthalpy of vaporization of water is 44.0kJ/mol = 2.44 kJ/g=2440 J/g

Q out=Q in

Q releases = Q absorbed

Q water = Q Aluminum

m.Lf = m.cs.ΔT

0.84 x 2440 J/g = 51 x 0.903 J/g C x (t-25)

2049.6=46.053(t-25)

t=69.5 °C

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