# How would you solve gas laws problems with the given "at STP"?

Nov 28, 2015

Refer to the Explanation.

#### Explanation:

The most current recommendation for $\text{STP}$ is ${0}^{\text{o""C}}$ $\left(\text{273.15 K}\right)$, and $\text{10"^5 "Pa}$$\left(\text{100 000) Pa}\right)$, which most people write as $\text{100 kPa}$ because its easier to work with, but is identical to $\text{10"^5 "Pa}$. Using these values, the molar volume of a gas is $\text{22.710 980 L/mol}$.

So if you are asked to find the volume of a gas at STP, you would use $\text{273.15 K}$ and $\text{100 kPa}$.

However, many people are still using ${0}^{\text{o""C}}$ ($\text{273.15}$) and $\text{1 atm}$. Using these values, the molar volume of a gas is $\text{22.414 L/mol}$.
https://en.wikipedia.org/wiki/Molar_volume

Whichever value you choose to use for STP, make sure the temperature is always in Kelvins (C+273.15), and that the gas constant, R, has the same units that correspond to your temperature and pressure, and be sure you have the correct molar volume if needed.
https://en.wikipedia.org/wiki/Gas_constant

http://en.citizendium.org/wiki/Reference_conditions_of_gas_temperature_and_pressure#cite_note-NISTCODATA-10