Final answer:
The sample of carbon with 1.281024 atoms is equivalent to 2.127 x 10^-24 moles. The mass of this sample is 2.553 x 10^-23 g.
Step-by-step explanation:
One mole of carbon has a mass of 12.0 g since it is nearly pure 12C. The molar mass of carbon is defined as the mass in grams that is numerically equal to the average atomic weight. Therefore, using the given information, we can calculate the number of moles and the mass of the sample of carbon.
Number of moles = Number of atoms / Avogadro's number
Mass = Number of moles x Molar mass
Given the sample has 1.281024 atoms,
Number of moles = 1.281024 / (6.022 x 10^23) = 2.127 x 10^-24 moles
Mass = 2.127 x 10^-24 moles x 12.011 g/mol = 2.553 x 10^-23 g