Question

The number of mole of nitrogen in one litre of air containing 10% nitrogen by volume, under standard conditions, is (1)0.03 moles (2)2.10moles (3)0.186moles (4)4.46 * 10 -3 mole

Answer 1

The volume of nitrogen in the mixture is:

10% of the mixture  =   10/100 x 1 liter
                                =    0.1 liters
Use ideal gas law to calculate the moles of the nitrogen gas.

Ideal gas law states that 1 mole of an ideal gas occupies 22.4 liters by volume.

Therefore, If 22.4 liters gives 1 mole,
                  then what will 0.1 mole give?  =  ( 0.1 x1/22.4) liters.
                               (use cross multiplication to come up with the answer)
 
                                              = 0.1/22.4
                                              
                                              = 4.46 x 10^-3

Hope you find this helpful.

Answer 2

Answer:

Volume percentage is defined as

Volume per cent = (volume of solute/ volume of solution)×100

Given the volume % is 10.

Let VN be the volume of N2 present in 1 litre of air.

Therefore we have,

10 = (VN/1)×100

VN = 10/100 = 0.1 litres of Nitrogen gas.

Now 22.4 litres of N2 gas = 1 mole of N2 gas.

Therefore 1 litre of N2 gas = 1/22.4 moles of N2 gas.

So 0.1 Litres of N2 gas = (1/22.4)×0.1 = 0.0045 moles.