• Molarity (M): Moles of solute per liter of solution. $M = \frac{\text{moles of solute}}{\text{liters of solution}}$
• Molality (m): Moles of solute per kilogram of solvent. $m = \frac{\text{moles of solute}}{\text{kg of solvent}}$
• Normality (N): Equivalents of solute per liter of solution. $N = M \times \text{number of reactive groups (H}^+ \text{or OH}^- \text{)}$
• Parts Per Million (ppm): Mass of solute per million mass units of solution. $\text{ppm} = \frac{\text{mass of solute}}{\text{mass of solution}} \times 10^6$ For dilute aqueous solutions, $1 \, \text{ppm} \approx 1 \, \text{mg/L}$.

Adding a solute raises the boiling point and lowers the freezing point of the solvent.

$\Delta T_b = i K_b m$ $\Delta T_f = i K_f m$

• $i$: Van 't Hoff factor (number of particles the solute dissociates into).
  • For NaCl, $i \approx 2$. For Glucose, $i = 1$.
• $K_b, K_f$: Boiling/Freezing point constants (e.g., Water: $K_b=0.512$, $K_f=1.86$).
• $m$: Molality.