The volume of a monatomic ideal gas doubles in an isothermal expansion. By what factor does its pressure change?

Respuesta :

Answer: The pressure of the gas changes by a factor of 2

Explanation:

An isothermal expansion is a process in which a gas expands (or contracts), keeping a constant temperature.

On the other hand, the expression for an Ideal Gas is:  

[tex]P.V=n.R.T[/tex] (1)

Where:  

[tex]P[/tex] is the pressure of the gas  

[tex]V[/tex] is the volume of the gas  

[tex]n[/tex] the number of moles of gas  

[tex]R[/tex] is the gas constant  

[tex]T[/tex] is the absolute temperature of the gas

Now, if the temperature keeps constant, we can use Boyle's law, which relates the volume and pressure of a certain amount of gas maintained at a constant temperature:

[tex]P_{1}V_{1}=P_{2}V_{2}[/tex] (2)

Where [tex]P_{1}V_{1}[/tex] are the initial pressure and initial volume of the gas and [tex]P_{2}V_{2}[/tex] are the final pressure and final volume of the gas.

If:

[tex]P_{1}V_{1}=n.R.T[/tex] (3)

[tex]P_{2}V_{2}=n.R.T[/tex] (4) where [tex]V_{2}=2V_{1}[/tex]

Then:

[tex]P_{1}V_{1}=P_{2}(2V_{1})[/tex] (5)

[tex]\frac{P_{1}}{P_{2}}=\frac{2V_{1}}{V_{1}}[/tex] (6)

[tex]\frac{P_{1}}{P_{2}}=2[/tex] (7)

Finally:

[tex]P_{1}=2P_{2}[/tex] (8) This means the pressure of the gas changes by a factor of 2.