What volume will 4.91×10^22 atoms of ar occupy at stp

1.765 dm³

Explanation:

Data Given:

Number of atoms of Ar = 4.91×10²² atoms

Volume of gas at STP = ?

Solution:

First we have to find number of moles of Argon

The formula used for this purpose

                 No. of moles = no. of atoms / Avogadro's number

where as

Avogadro's number = 6.23 x 10²³

Put values in the equation

                 No. of moles = 4.91×10²² atoms / 6.23 x 10²³

                 No. of moles =  0.0788

So,

Number of moles of Ar is 0.0788

Now

we have to find volume of argon gas

Formula used for this purpos

                  No. of moles = Volume / molar volume

modified form of the above equation at STP for Argon

                 No. of moles Ar = Volume of Ar / 22.4 dm³/ mol . . . . . .(1)

Put values in equation 1

                0.0788 = Volume of Ar / 22.4 dm³/ mol

rearrange above equation

                Volume of Ar = 0.0788 x 22.4 dm³/ mol

                Volume of Ar = 1.765 dm³

So,

the volume of 4.91×10²²atoms of Ar at STP is 1.765 dm³

pure substance: iron,copper

impure substance: water,charcoal