Question

Pls help! WIL GIVE MEDAL
If the densities of two gases are measured at the standard temperature and pressure(STP), what does it mean?

Answer 1

it means that you have a fair way of comparing them amongst themselves and also relative to other gases that were measured in the same way. Eg Air in the sahara will be mush less dense in the day than at night as the temp varies so much over the course of 24 hours. i.e. a given volume of air will weigh less in the day.

from a reliable website:

"STP is commonly used to define standard conditions for temperature and pressure which is important for the measurements and documentation of chemical and physical processes:

STP - Standard Temperature and Pressure - is defined by IUPAC (International Union of Pure and Applied Chemistry) as air at 0oC (273.15 K, 32 oF) and 105 pascals
STP - commonly used in the Imperial and USA system of units - as air at 60 oF (520 oR) and 14.696 psia (15.6oC, 1 atm)"