How many moles of atoms are in each elemental sample? A. 1.24 g Zn
B. 28.1 g Ar
C. 84.0 g Ta
D. 2.29x10^-2 g Li

Moles = mass(m) / Molar mass (M)

A. 1.24g of Zn

m = 1.24g

M = 65.4 g/mol

moles of Zn = 1.24g/ 65.4g/mol

= 0.01896mol

B. 28.1 g Ar

m = 28.1g

M(Ar) = 39.9g/mol

moles of Ar = 28.1g/39.9g/mol

= 0.7043 mol

C. 84.0 g Ta

m = 84.0g

M(Ta) = 181g/mol

moles of Ta = 84.0g/181g/mol

= 0.4641 mol

D. 2.29x10^-2 g Li

m = 2.29x10^-2 g

M(Li) = 6.9g/mol

moles of Li = 2.29x10^-2 g / 6.9g/mol

= 0.0033 mol

Hope this helps