## Concentration
- amount of solute per volume of solvent - e.g. g / L
- relative terms - "concentrated" or "dilute"
+- mg / L = ppm = $\mu$g / g
+
+## Molarity
+- special concentration unit in mol / L (abbbreviation M)
+$$c={n \over v}$$
+
+$$c_1v_2=c_2v_2=n\quad\leftarrow(\operatorname{constant})$$
+
+| Quantity | Symbol | Unit |
+| ---------------------- | ------- | ------------- |
+| molar mass | $M$ | g / mol |
+| molar concentration | $c$ | mol / L ($M$) |
+| specific heat capacity | $c$ | J / g / K |
+
+## Precipitation reactions
+Ions in solution combine to form a new compound.
+Occurs when concentration exceeds solubility.
+Precipitation reactions happen when water cannot dissociate ionic lattice structure.
+Precipitate (product):
+
+- generally insoluble in water
+- forms as solid particles that settle
+- forms from compounds insoluble in water
+
+All group 1 ions are soluble.
+
+**Ions swap between reactants**
+
+## Ionic equations
+
+Used when a salt (ionic) dissolves into constituent ions.
+"Spectator" ions - ions that do not dissolve or precipitate in reaction. **Not** included in equations.