1) H_{2}

Step One: the molar mass of H_{2} is 2.016 g/mol

Step Two: 2.016 g/mol ÷ 6.022 x 10^{23} mol¯^{1} = 3.348 x 10¯^{24} g

2) PCl_{5}

Step One: the molar mass of PCl_{5} is 208.239 g/mol

Step Two: 208.239 g/mol ÷ 6.022 x 10^{23} mol¯^{1} = 3.458 x 10¯^{22} g

3) UF_{6}

Step One: the molar mass of UF_{6} is 352.019 g/mol

Step Two: 352.019 g/mol ÷ 6.022 x 10^{23} mol¯^{1} = 5.846 x 10¯^{22} g

4) F

Step One: the molar mass of F_{2} is 37.997 g/mol

Step Two: 37.997 g/mol ÷ 6.022 x 10^{23} mol¯^{1} = 6.310 x 10¯^{23} g

5) CH

Step One: the molar mass of CH_{4} is 16.043 g/mol

Step Two: 16.043 g/mol ÷ 6.022 x 10^{23} mol¯^{1} = 2.664 x 10¯^{23} g

You may have noticed the use of the unit mol¯^{1} on Avogadro's Number. This unit means "1/mol" or "per mole." The numerator label is not written because it is (usually) unimportant if we are discussing atoms, molecules, ions, or whatever. In addition, the contxt often supplies what the numerator should be. In the cases above, it would be "molecule."

It also may be important for you to satisfy yourself that the units of "mol" do, in fact, cancel. Return Some Additional Problems