Question

Calculate the number of moles in 560ml of n2 at stp

Answer 1

no. if moles = given volume /22400

= 560/22400

=1/40

=0.025 mol

Answer 2

Explanation:

The idea here is that you need to use the fact that at STP conditions, one mole of any ideal gas occupies exactly

22.7 L

- this is known as the molar volume of a gas at STP.

This means that if you know the volume of the gas, you can determine how many moles the sample contains by using the known molar volume at STP

560

mL

⋅

1

L

1000

mL

⋅

1 mole

22.7

L

=

0.02467 moles

The molar mass of the compound, which tells you what the exact mass of one mole of the gas is, can be determined by using the mass of the sample.

M

M

=

m

n

M

M

=

1.10 g

0.02467 moles

=

44.59 g/mol

Rounded to two sig figs, the nswer will be

M

M

=

45 g/mol