Problem 29P

How many moles of atoms are in each elemental sample?

(a) 1.34 gZn

(b) 24.9 gAr

(c) 72.5 gTa

(d) 0.0223 g Li

Solution 29P

Here, we have to determine the number of moles of atoms are in each elemental sample.

(a) 1.34g Zn :

Molar mass of Zinc(Zn) = 65.38 g/mol.

This means 1 mol of Zn is 65.38g .

To find the number of moles of Zn, we divide the given amount of Zn by the molar mass of Zn.

=

= 0.020 mole

Hence, 1.34 g of Zn contains 0.020 moles of Zinc.

(b) 24.9g Ar :

Molar mass of Argon(Ar) = 39.948 g/mol.

This means 1 mol of Ar is 39.948 g .

To find the number of moles of Ar, we divide the given amount of Ar by the molar mass of Ar.

=

= 0.623 mole

Hence, 24.9 g of Ar contains 0.623 moles of Argon.

(c) 72.5g Ta :

Molar mass of Tantalum(Ta) = 180.94 g/mol.

This means 1 mol of Ta is 180.94 g .

To find the number of moles of Ta, we divide the given amount of Ta by the molar mass of Ta.

=

= 0.400 mole

Hence, 72.5 g of Ta contains 0.400 moles of Tantalum.

(d) 0.0223g Li :

Molar mass of Lithium(Li) = 6.941 g/mol.

This means 1 mol of Li is 6.941g .

To find the number of moles of Li, we divide the given amount of Li by the molar mass of Li.

=

= 0.0032 mole

Hence, 0.0223 g of Li contains 0.0032 moles of Li.