How do you calculate the number of moles from molarity and volume?

1 Answer
Jan 8, 2014

Answer:

You multiply the molarity by the volume in litres.

Explanation:

Molarity is the number of moles of a substance in one litre of solution. The official symbol for molarity is “c” (concentration), but many people use the old symbol “M”.

#M = n/V#, 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#

Example
:
How many moles of #"NaCl"# are contained in 0.300 L of 0.400 mol/L #"NaCl"# solution?

Solution:

#n = 0.300 color(red)(cancel(color(black)("L soln"))) × "0.400 mol NaCl"/(1 color(red)(cancel(color(black)("L soln")))) = "0.120 mol NaCl"#