Question

1.) You have 4.2 moles of magnesium (Mg). How many atoms of magnesium do you have?

Answer 1

1) N = 4,2 moles
M = 24,31 u
m = N x M
= 4.2 x 24.31 = 102.102 kg


2) m = 54.9 grams = 0.0549 kilograms
M (Na) = 22.99 u
N (moles) = m / M
N = 0.0549 / 22.99 = 2.4 x 10^-3 moles

I don’t know if it helped you a bit :)