*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