At standard temperature and pressure, a given sample of water vapor occupies a volume of 2.8 0 L. How many moles of water vapor are present?
1 Answer
Explanation:
The idea here is that an ideal gas kept under Standard Temperature and Pressure (STP) conditions has a molar volume equal to
In other words, when pressure is set to
So, if your sample of water vapor occupies
2.80 color(red)(cancel(color(black)("L"))) * overbrace("1 mole"/(22.7color(red)(cancel(color(black)("L")))))^(color(purple)("molar volume of a gas at STP")) = "0.12335 moles"
of water vapor. You need to round this off to three sig figs, the number of sig figs you have for the volume of water vapor
"no. of moles of water vapor" = color(green)(|bar(ul(color(white)(a/a)"0.123 moles"color(white)(a/a)|)))
It's worth noting that many textbooks and online sources still list STP conditions as a pressure of
Under these conditions, one mole of any ideal gas occupies