How do you calculate the number of moles from concentration?
You multiply the concentration (in moles per litre) by the volume in litres.
The number of moles of a substance in one litre of solution is called its molarity. The official symbol for molarity is “c” (concentration), but most people use the symbol “M”.
where n is the number of moles and V is the volume in litres.
We can rearrange this equation to get the number of moles:
n = M × V
How many moles of NaCl are contained in 0.300 L of 0.400 mol/L NaCl solution?
n = 0.300 L soln × (0.400 mol NaCl/1 L soln) = 0.120 mol NaCl