Question #461b0
1 Answer
Explanation:
The idea here is that under STP conditions, which are defined as a pressure of
Since you know that
#"1 dm"^3 = 10^3 quad "cm"^3#
you can say that at STP,
You can use the molar volume of a gas at STP to find the number of moles of oxygen as present in your sample.
#220 color(red)(cancel(color(black)("cm"^3))) * "1 mole O"_2/(2.271 * 10^4 color(red)(cancel(color(black)("cm"^3)))) = 9.687 * 10^(-3) quad "moles O"_2#
To convert the number of moles of oxygen gas to moles, you can use the molar mass of oxygen gas.
#9.687 * 10^(-3) color(red)(cancel(color(black)("moles O"_2))) * "32.0 g"/(1color(red)(cancel(color(black)("mole O"_2)))) = color(darkgreen)(ul(color(black)("0.31 g")))#
The answer is rounded to two sig figs, the number of sig figs you have for the volume of oxygen gas.