A gaseous compound composed of sulfur and oxygen, which is linked to the formation of acid rain, has a density of 3.58 g/L at STP. What Is the molar mass of this gas?
Your strategy here will be pick a sample of this gas and use the definition of the molar volume of a gas at STP to help you find the number of moles it contains.
To make the calculations easier, let's say that we're going to pick a
As you know, one mole of any ideal gas occupies exactly
So, if one mole of this gas will occupy
#1.00 color(red)(cancel(color(black)("L"))) * "1 mole"/(22.71 color(red)(cancel(color(black)("L")))) = "0.04403 moles"#
According to the given density, this
#color(blue)("molar mass" = "mass in grams"/"number of moles")#
This means that the gas' molar mass will be
#M_"M" = "3.58 g"/"0.04403 moles" = color(green)("81.3 g/mol")#
SIDE NOTE It is very likely that this problem meant for you to use the old definition of STP, which is a pressure of
In this case, the molar volume of a gas at STP is equal to 22.4 L. This in turn will make the molar mass of the gas equal to