*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 <span><span> <u> 1 mol C </u></span><u> </u></span> = 1.599 mol C 12.011 g C <span> </span>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 <u> 6.022x10^23 atoms Cu </u> = 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 <u> 31.998 g O2 </u> = 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 <u> 1 mol Ag </u> = 10.810 mol Ag 6.022x10^23 atoms Cu