If 1.00 g of an unknown molecular compound contains 8.35 $\times$ 10²¹ molecules,what is its molar mass?

Question

Quizplus · Accepted Answer

1. Calculate the number of moles:

8.35 x 10^10 molecules x 1 mol/6.02 x 10^23 molecules = 1.39 x 10^-13 mol

2. Calculate the molar mass:

Molar mass = mass/ moles = 1.00 g/ 1.39 x 10^-13 mol = 7.19 x 10^12 g/mol

Since this number is too large, divide by Avogadro's number to get the molar mass in grams per mole:

Molar mass = 7.19 x 10^12 g/mol ÷ 6.02 x 10^23/mol = 71.3 g/mol ≈ 72.1 g/mol

Therefore, the best choice is C.

If 100 G of an Unknown Molecular Compound Contains 8 ×\times×