# A sample of argon has a volume of 205 cm^3 when it's temperatures is -44 degrees C. and its pressure is 712 mm of Hg. What would be the volume of the argon at STP?

Jul 3, 2017

We use the combined gas law, which states for a GIVEN quantity of gas..........$\frac{{P}_{1} {V}_{1}}{T} _ 1 = \frac{{P}_{2} {V}_{2}}{T} _ 2$; and we eventually get ${V}_{2} \cong 230 \cdot c {m}^{3}$

#### Explanation:

$T$ is always expressed as $\text{temperatura assoluta}$, which sets absolute zero at $0 \cdot K \equiv - 273.15$ ""^@C. And depending on your syllabus, $S T P$ specifies a temperature of $273.15 \cdot K$, and a pressure of $1 \cdot a t m$. And we know that $1 \cdot a t m$ will support a column of mercury that is $760 \cdot m m$ high.........

We want ${V}_{2} = \frac{{P}_{1} \times {V}_{1} \times {T}_{2}}{{P}_{2} \times {T}_{1}}$.....

And already we see from the quotient we ARE going to get an answer with $\text{VOLUME units........}$ as required.

${V}_{2} = \frac{712 \cdot m m \cdot H g \times 205 \cdot c {m}^{3} \times 273.15 \cdot K}{760 \cdot m m \cdot H g \times 229.15 \cdot K}$

$\cong 230 \cdot c {m}^{3}$...........