Concentration Units

Concentration is defined as the amount of solute present in a given amount of solvent or solution. It is also the ratio of amount of solute to the amount of solution or ratio of amount of solute to the amount of solvent.

Percentage

1. Mass by mass percent (%m/m) It is the mass of solute in gram dissolve in 100 gram of solution. For example, 5% m/m sugar solution means that 5 grams of sugar dissolved in 95 grams of water to make 100 grams of solution.

   $Percentage \:Solution \:\large(\frac{m}{m})$ % $= \large \frac{Mass \:of \:Solute (g)}{Mass\: of \:Solute \:(g) + Mass\: of \:Solvent \:(g)} \times 100$

   $Percentage \:Solution \:\large(\frac{m}{m})$ % $= \large \frac{Mass \:of \:Solute (g)}{ Mass\: of \:Solution \:(g)} \times 100$

2. Mass by volume percent (%m/v) It is the mass of the solute in grams dissolved per 100ml of the solution. For example, 5%m/v sugar solution means that 5 grams of sugar in 100ml of the solution.

   $Percentage \:Solution \:\large(\frac{m}{v})$ % $= \large \frac{Mass \:of \:Solute (g)}{Volume\: of \:Solution \:(ml)} \times 100$

3. Volume by mass percent (%v/m) It is the volume of solute in cm dissolved in 100 grams of the solution. For example, 5%(v/m) solution means 5ml of alcohol is dissolved in (unknown) volume of water so that mass of solution become 100g.

   $Percentage \:Solution \:\large(\frac{v}{m})$ % $= \large{ \frac{Mass \:of \:Solute (g)}{Volume\: of \:Solution \:(g)}} \times 100$

4. Volume by volume percent (%v/v) The volume of solute in ml is dissolved per 100 ml of the solution. For example, 5%(v/v) solution means that 5ml of alcohol is dissolved in 95ml of the water to make 100 cm of the solution.

   $Percentage \:Solution \:\large(\frac{v}{v})$ % $= \large{ \frac{Volume \:of \:Solute (ml)}{Volume\: of \:Solution \:(ml)}} \times 100$

Molarity

It is a concentration unit defined as number of moles of solute dissolved in one 3 dm of the solution. It is represented by M. Molarity is the unit mostly used in chemistry and allied sciences. The formula used for the preparation of molar solution is as follows:

$Molarity (M)$ $= \large{ \frac{Number \:of \: moles \: of \:Solute (mol)}{Volume\: of \:Solution \:in \:L}}$

$Molarity (M)$ $= \large{ \frac{ mass \: of \:Solute \:(g)}{Molar\: mass\: of \:the \:Solute \: (g/mol)}}\times \large{ \frac{1000}{Volume\: of \:Solution \:in \:ml}}$