Question

The volume of gas decreases at constant temperature to 80% of the inital value. How does the pressure value change relative to the initial value

Answer 1

Answer:

The pressure value changes 400 % relative to the initial value.

Explanation:

Let suppose that the gas behaves ideally and represents a closed system, that is, a system with no mass interactions so that number of moles is conserved ($n$). Since the variables involved in the isothermal process are pressure ($P$) and volume ($V$). Finally, the process is represented by the following relationship:

$P_{1}\cdot V_{1} = P_{2}\cdot V_{2}$ (1)

Where:

$P_{1}, P_{2}$ - Initial and final pressures.

$V_{1}, V_{2}$ - Initial and final volumes.

If we know that $P_{1} = P_{o}$, $V_{1} = V_{o}$ and $V_{2} = 0.2\cdot V_{o}$, then the final pressure of the closed system is:

$P_{2} = P_{1}\cdot \left(\frac{V_{1}}{V_{2}} \right)$

$P_{2} = 5\cdot P_{o}$

The pressure value changes 400 % relative to the initial value.