Calculating Percentage and Parts per Million in Solutions

Concentration of Solutions

• W% (Mass percentage) is defined as the mass of solute in the solution per 100 g of the solution.
• W% = (Mass of solute in the solution × 100) / Total mass of the solution

Volume Percentage

• V% (Volume percentage) is defined as the volume of solute dissolved per 100 mL of solution.
• V% = (Volume of solute × 100) / Total volume of the solution

Mass by Volume Percentage

• w% (Mass by volume percentage) is defined as the mass of solute dissolved per 100 mL of solution.
• w% = (Mass of solute × 100) / Volume of solution

Parts Per Million (ppm)

• ppm is defined as the parts of a component per million (10^6) parts of the solution.
• ppm can be expressed in three ways: mass to mass, volume to volume, and mass to volume.

Mole Fraction

• Mole fraction is the ratio of the number of moles of a particular component to the total number of moles of all the components.
• χA = nA / (nA + nB), where nA is the number of moles of component A and nB is the number of moles of component B.

Key Formulae

• Mole fraction of a component = x1 = n1 / (n1 + n2)
• Molarity (M) = Number of moles of solute / Volume of solution in Litre
• Molality (m) = Number of moles of solute / Mass of solvent in kg
• Normality (N) = Number of gram equivalents of solute / Volume of solution in Litre

Relationships between Concentration Terms

• Relationship between Molarity (M) and Molality (m): dM / (1 - B) = M / 1000m
• Relationship between Mole fraction of solute (χB) and Molality (m): m = χB × 1000 / (1 - χB) × MA

Molarity and Molality

• Molarity (M) is defined as the number of moles of solute per litre of solution.

• M = WB × 1000 / MB × V

• Unit of Molarity is mol L^-1 or M (molar).

• Molality (m) is defined as the number of moles of solute per 1000 g or 1 kg of solvent.

• m = WB × 1000 / MB × W

• Unit of Molality is mol kg^-1 or molal (m).