A solution can be described as concentrated or dilute. These terms are relative to one another and only tell you if a solution contains many particles of solute per particles of solvent (concentrated) or few particles of solute per particles of solvent (dilute). The percent concentration is a measurement used to tell us exactly how many particles of solute per solvent particles are present in a given solution.

You should become familiar with the following expressions for percent concentration: mass/mass percent, volume/volume percent and mass/volume percent. Pay close attention to the units in each expression.

 
 

Mass/mass Percent	=	grams of solute	x	100
		grams of solution

 
 

Volume/volume Percent	=	mL of solute	x	100
		mL of solution

 
 

Mass/volume Percent	=	grams of solute	x	100
		mL of solution

 

Questions:

What is the mass/volume percent, % (m/v), of sodium hydroxide solution if 20 g of NaOH is dissolved in 312 mL of water?
 

% (m/v)	=	20 g NaOH	x	100	=	6.4%
		312 mL H2O

 

Question:

How many grams of NaOH are in 450 mL of a 5.0% (m/v) NaOH solution?

 
 

450 mL	x	5.0 g NaOH	=	22.5 g NaOH
		100 mL H2O

 
 

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