Question

Под поршнем в цилиндрическом сосуде (ось цилиндра вертикальна) находится водяной пар с температурой t =100°C при давлении p = 70 кПа. Поршень опустили,уменьшив объем содержимого сосуда изотермически в n = 1 .5 раз. Каким стало давление в сосуде? Ответ записать в МПа, округлив до десятых

Answer 1

P1 - первоначальное давление, Р2 - давление после сжатия поршня 
V1=1,5*V2
P1*V1/T1=P2*V2/T2
т.к. процесс изотермический, то P1V1=P2V2
получаем
1,5*P1*V2=P2*V2
1,5*P1*V2=P2
P2=1,5*70*1000=105000 Па=0,1МП
Ответ: Р2=0.1 МПа

Answer 2

Problem Analysis

We are given a cylindrical vessel with a piston, and it contains water vapor at a temperature of 100°C and a pressure of 70 kPa. The volume of the vessel is reduced isothermally by a factor of 1.5. We need to determine the new pressure inside the vessel.

Solution

To solve this problem, we can use the ideal gas law, which states that the pressure of a gas is inversely proportional to its volume when the temperature and the amount of gas are constant. The equation can be written as:

P1 * V1 = P2 * V2

Where: - P1 is the initial pressure - V1 is the initial volume - P2 is the final pressure - V2 is the final volume

In this case, the volume is reduced by a factor of 1.5, so V2 = V1 / 1.5.

We can substitute the given values into the equation and solve for P2.

Calculation

Given: - P1 = 70 kPa - V2 = V1 / 1.5

Substituting the values into the equation:

P1 * V1 = P2 * (V1 / 1.5)

Simplifying the equation:

P2 = (P1 * V1) / (V1 / 1.5)

P2 = P1 * (1.5 / V1)

Now, we need to convert the pressure from kPa to MPa and round the answer to the nearest tenth.

Answer

The pressure inside the vessel after reducing the volume is 0.1 MPa.