how many atoms are there in 1.4g C

Question

How many atoms are in 1.4grams C?  Answer in atoms. 

Answer 1

Divide the given mass (m) by the atomic weight (W) of C to get the number of moles (n), then multiply by Avogadro's number (A) to get the number of atoms (N).

 

Atomic weight of C:  W = 12.01 g/mole

 

n = m/W = 1.4 g / (12.01 g/mole) = 0.1166 moles

 

N = nA = (0.1166 moles)(6.02 x 10²³ atoms/mole) ≅ 7.02 x 10²² atoms

 

There are about 7.02 x 10²² carbon atoms in 1.4 g of carbon