After admitting 20 g of water vapor at 100 ° C into the calorimeter containing 500 g

| June 11, 2021 | education

After admitting 20 g of water vapor at 100 ° C into the calorimeter containing 500 g of water, a temperature of 50 ° C was established there. What was the initial water temperature?

mw = 500 g = 0.5 kg.

t = 50 ° C.

tp = 100 ° C.

mp = 20 g = 0.02 kg.

Cw = 4200 J / kg * ° C.

λ = 2.3 * 10 ^ 6 J / kg.

tv -?

Qp = Cw * mp * (tp – t) + λ * mp.

Qw = Cw * mw * (t – tv).

Qп = Qв.

Cw * mp * (tp – t) + λ * mp = Cw * mw * (t – tv).

Cw * mp * tp – Cw * mp * t + λ * mp = Cw * mw * t – Cw * mw * tv.

Cw * mw * tw = Cw * mw * t + Cw * mp * t – Cw * mp * tp – λ * mp.

tv = (Cw * mw * t + Cw * mp * t – Cw * mp * tp – λ * mp) / Cw * mw.

tv = (4200 J / kg * ° C * 0.5 kg * 50 ° C + 4200 J / kg * ° C * 0.02 kg * 50 ° C – 4200 J / kg * ° C * 0.02 kg * 100 ° C – 2.3 * 10 ^ 6 J / kg * 0.02 kg) / 4200 J / kg * ° C * 0.5 kg = 26 ° C.

Answer: the water in the calorimeter had a temperature of tв = 26 ° C.



One of the components of a person's success in our time is receiving modern high-quality education, mastering the knowledge, skills and abilities necessary for life in society. A person today needs to study almost all his life, mastering everything new and new, acquiring the necessary professional qualities.