How would you know when you had a mole of a substance for which you knew the formula?

1 Answer
Mar 26, 2018

Answer:

You determine the molar mass (mass of one mole) of the substance. Then obtain that mass using a laboratory balance, and you will have one mole of the substance.

Explanation:

Example:

Obtain one mole of calcium chloride #("CaCl"_2")#.

Determine the molar mass of #"CaCl"_2"# by multiplying the subscript of each element by its molar mass (atomic weight on the periodic table in g/mol).

Molar mass #"CaCl"_2":#

#(1xx"40.078 g/mol Ca") + (2xx"35.453 g/mol Cl")="110.984 g/mol"#

Use a balance to mass out #"110.984 g CaCl"_2"#. This is one mole of calcium chloride.