Sofia A. answered 07/20/22
AP Chemistry Tutor with a PhD and College Teaching Experience
A 0.503 g sample of steam at 107.1 ∘C is condensed into a container with 5.92 g of water at 14.5 ∘C. What is the final temperature of the water mixture if no heat is lost? The specific heat of water is 4.18 J / g⋅ ∘C, the specific heat of steam is 2.01 J / g⋅∘C, and Δ𝐻vap=40.7 kJ/mol
The amount of heat released when 0.503 g vapor are condensed at 100∘C is
Q = 0.503 g x 7.1∘C x 2.01 J / g⋅∘C + 0.503 g x 40.7 kJ/ mol / (18.0 g/mol) = 7.18 J + 1,137 J = 1,144 J
This amount of heat could raise the temperature of the 5.92 g of water initially at 14.5 ∘C to
14.5 ∘C + 1,144 J / (4.18 J / g ∘C x 5.92 g) = 60.7∘C
Finally we need to calculate what happens if 5.92 g water at 60.7∘C were mixed with 0.503 g at 100∘C.
The final temperature is given by
60.7∘C + (100-60.7) x 0.503 / (5.92 + 0.503) = 60.7∘C + 3.1∘C = 63.8 ∘C