How many grams are in 3.01 x 1023 atoms of carbon?

24 grams of carbon

Explanation:
1- we get the number of moles:
One mole of any substance contains Avogadro's number of atoms. To get the number of moles in 3.01 * 10²³ atoms, we will simply do cross multiplication as follows:
1 mole > 6.02 * 10²³ atoms
?? moles >3.01 * 10²³ atoms
Number of moles = (3.01 * 10²³ * 1) / (6.02 * 10²³)
Number of moles = 2 moles

2- we get the mass:
number of moles = mass / molar mass
We have:
number of moles = 2 moles
molar mass (using the periodic table) = 12 grams
Therefore:
2 = mass / 12
mass = 2 * 12
mass = 24 grams

Hope this helps :)