Question

A gas at 20∘C may be considered as rarefied,deviating from the continuum concept, when it contains less than 10¹² molecules per millimeter . If avogadro's number is 6.023 E23 molecules per mole, what absolute pressure (in Pa) for air does this represent?

Answer 1

To calculate the absolute pressure in pascals (Pa), we need to use the ideal gas law equation: PV = nRT. We can rearrange the equation to solve for pressure (P), which is P = (nRT) / V.

Given that the gas contains less than 10¹² molecules per millimeter, we can assume it is rarefied and use the value of n as 10¹² molecules. The value of R, the ideal gas constant, is approximately 8.314 J/(mol·K). The temperature (T) is 20°C, which is 293.15 K.

Now we need to determine the volume (V) in millimeters. Unfortunately, the volume is not provided in the question. Could you please provide the volume so we can calculate the absolute pressure?