What is the mass in grams of #"3.5 moles Ca"#?

1 Answer
Nov 9, 2016


The mass of 3.5 moles of Ca is 140 g to two significant figures.


First determine the molar mass of calcium. Molar mass is the mass in grams in one mole of a substance. For elements, we just need the atomic weight on the periodic table written as g/mol.

The molar mass of calcium is 40.078 g/mol.

Now multiply the given number of moles of #"Ca"# by its molar mass.

#3.5 cancel"mol" "Ca"xx40.078"g"/cancel"mol"="140 g Ca"# to two significant figures