Answer:
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
