Aqueous Systems The wonder of water

Water as a liquid High surface tension and low vapor pressure are due to hydrogen bonding

Water as a solid Water actually expands slightly as the tendency to actually arrange in a lattice moves the molecules farther apart than when in the liquid state

Terminology Solvent: the dissolving medium Solute: that which is dissolved Aqueous solution: solution with water as the solvent Solvation: the process of a solute dissolving, becoming surrounded by solvent molecules

Electrolytes and nonelectrolytes Electrolytes: compounds, when in an aqueous state or molten, that will conduct electricity; this occurs because the ions of the compound become mobile. Non-electrolytes: see above. Basically, molecular compounds that are not composed of ions. Strong vs. weak: degree of ionization

Hydrates Compounds with “bound” water as part of the formula. Example: CuSO4·5H2O Example: MgSO4·7H2O Efflorescence: the process of losing this water Hygroscopy: the process of removing water from the atmosphere, absorbing it. Compounds like this are hygroscopic or deliquescent (will form solutions).

More Aqueous systems Suspensions: a solution where the particles can separate over time Colloids: heterogeneous mixture whose particles are smaller than a suspension and display the Tyndall Effect, that is they scatter light