Question

Какое количество теплоты выделится при конденсации 200г водяного пара, имеющего температуру 100С, и охлаждение образовавшейся воды до температуры 40С?

Answer 1

Q=Lm           L=2300*1000 Дж/кг
Q=cm(t2-t1)             c=4200 Дж/кг
Q1=2300000*0,2=460000Дж - при конденсации
Q2=4200*0,2(100-40)=50400Дж - при охлаждении
Q=460000+50400=510400 Дж - всего

Answer 2

Calculating Heat Released During Condensation and Cooling of Water

To calculate the heat released during the condensation of 200g of water vapor at 100°C and the subsequent cooling of the formed water to 40°C, we can use the following steps:

1. Heat Released During Condensation: - The heat released during the condensation of water vapor can be calculated using the formula: \[ Q_1 = m \times L \] where \( Q_1 \) is the heat released, \( m \) is the mass of the substance undergoing the phase change, and \( L \) is the latent heat of vaporization.

- From the given information: - Mass of water vapor, \( m = 200g \) - Latent heat of vaporization of water at 100°C, \( L = 539 \, cal/g \).

- Substituting the values: \[ Q_1 = 200g \times 539 \, cal/g = 107800 \, cal \]

- Therefore, the heat released during the condensation is \( 107800 \, cal \).

2. Heat Released During Cooling of Water: - The heat released during the cooling of water can be calculated using the formula: \[ Q_2 = m \times c \times \Delta T \] where \( Q_2 \) is the heat released, \( m \) is the mass of the substance, \( c \) is the specific heat capacity, and \( \Delta T \) is the change in temperature.

- From the given information: - Mass of water, \( m = 200g \) - Specific heat capacity of water, \( c = 1 \, cal/g°C \) - Change in temperature, \( \Delta T = 60°C \) (from 100°C to 40°C).

- Substituting the values: \[ Q_2 = 200g \times 1 \, cal/g°C \times 60°C = 12000 \, cal \]

- Therefore, the heat released during the cooling of water is \( 12000 \, cal \).

Total Heat Released:

The total heat released during the condensation of 200g of water vapor at 100°C and the subsequent cooling of the formed water to 40°C is the sum of the heat released during condensation and the heat released during cooling: \[ Q_{total} = Q_1 + Q_2 = 107800 \, cal + 12000 \, cal = 119800 \, cal \]

Therefore, the total heat released is 119800 calories.