Question

What is the volume occupied by `"10.23"` moles of nitrogen gas at STP?

Answer 1

`"232.3 L"`

Explanation:

STP conditions are currently defined as a pressure of `"100 kPa"` and a temperature of `0^@"C"`. The thing to remember about gases kept under STP conditions is that one mole of any ideal gas will always occupy `"22.71 L"`.

In other words, if you know how many moles of gas you have under STP conditions, you can use the molar volume of a gas, which is equal to `"22.71 L mol"^(-1)`, as a conversion factor to help you find the volume occupied by the sample.

In your case, the sample contains `10.23` moles of nitrogen gas kept under STP conditions. This means that the volume of the sample will be

`10.23 color(red)(cancel(color(black)("moles N"_2))) * overbrace("22.71 L"/(1color(red)(cancel(color(black)("mole N"_2)))))^(color(blue)("molar volume of a gas at STP")) = color(green)(|bar(ul(color(white)(a/a)color(black)("232.3 L")color(white)(a/a)|)))`

The answer is rounded to four sig figs.

SIDE NOTE More often than not, the definition of STP conditions will be given to you as a pressure of `"1 atm"` and a temperature of `0^@"C"`.

Under these conditions, the molar volume of a gas is equal to `"22.423 L mol"^(-1)`. If this is the definition given to you, simply redo the calculation using `"22.423 L"` instead of `"22.71 L"`.