Question

How many moles of carbon are there in 19.2g of carbon?

Answer 1

*Necessary Information for the calculations*
Molar mass of carbon                  - 12.011 g/mol
Molar mass of copper                  - 63.546 g/mol
Molar mass of molecular oxygen - 31.998 g/mol
Avogadro's number                      - 6.022 x 10^23 atoms/mol

1. Moles of carbon in 19.2 grams of carbon (C)

To determine the number of moles carbon for a given mass of the substance, the mass of the sample is simply divided by its molar mass. Thus,

            19.2 g C  x      1 mol C           = 1.599 mol C
                                 12.011 g C

2. Atoms of copper in 11.4 moles of copper (Cu)

To determine the number of atoms of a substance for a given number of moles, the latter is simply multiplied by Avogadro's number which represents the number of particles, molecules, or atoms of a any substance in 1 mole. Thus, 

            11.4 mol Cu   x   6.022x10^23 atoms Cu     = 6.865x10^24 atoms Cu
                                                1 mole Cu

3. Mass of 3.15 moles of molecular oxygen (O2)

To determine the mass of a given number of moles of a substance, the former is simply multiplied by the molar mass of the substance. Thus,

            3.15 mol O2   x   31.998 g O2     = 100.794 g O2
                                         1 mole O2

4. Moles of silver in 6.51x10^24 moles of silver (Ag)

To determine the number of moles of a substance for a given number of atoms, the latter is simply divided by Avogadro's number. Thus, 

            6.51x10^24 atoms Ag   x             1 mol Ag                 = 10.810 mol Ag
                                                      6.022x10^23 atoms Cu