Question

Calculate the number of atoms in a 1.74 × 10³ g sample of carbon.

Answer 1

Mass of C = 1.74 *10^3 g = 1740 g
Molar mass of C = 12 g/mol
So,
number of moles of C = mass / mnolar mass
                      = 1740/12
                      = 145 mol
                  
1 mol = 6.022*10^23 atoms

So,
number of atoms = number of moles * 6.022*10^23
                = 145 * 6.022*10^23
               = 8.73*10^25 atoms
              
Answer: 8.73*10^25 atoms