How many carbon atoms are there in 45g of carbon?

Answer: 2.26x 10²⁴ atoms C

Explanation: To get the number of atoms,

First we convert mass of C to moles

45g C x 1mole C / 12 g C

= 3.75 moles C

Cancel g of C

Next convert moles of C to atoms using Avogadro's Number.

3.75 moles C x 6.022x10²³ atoms C / 1 mole C

Cancel out the units of moles C.

= 2.26x 10²⁴ atoms of C