polyatomic ions

coulombs law - like charges repel, unlike charges attract

force of attraction = constant Q1+Q2d2\frac{Q_1+Q_2}{d^2} where d=distance betwen ions, Q1=charge of cation and !2=charge of anion

when applied to energy instead of force it is Potential energy=U=constantQ1+Q2d\frac{Q_1+Q_2}{d^{}}

higher U means a higher melting point

Polyatomic ions

ammonium - NH4+

hydronium - H3O+

hydroxide - OH−

acetate - CH3COO−

nitrate - NO3−

permanganate - MnO4−

hydrogen carbonate - HCO3−

carbonate - CO32−

hydrogen sulfate - HSO4−

sulfate - SO42−

phosphate - PO43−

Naming molecules

  1. Mono-: 1 (often omitted for the first element)

  2. Di-: 2

  3. Tri-: 3

  4. Tetra-: 4

  5. Penta-: 5

  6. Hexa-: 6

  7. Hepta-: 7

  8. Octa-: 8

  9. Nona-: 9

  10. Deca-: 10

Solubility

Solutions are defined as uniform mixtures of two or more pure substances

The solvent is present in greatest abundance (normally water)

All other substances are solutes

Electrolyte: any substance that dissociates into ions when dissolved in a suitable medium and thus forms a conductor of electricity

Strong electrolyte dissociates completely (like NaCl

Weak electrolyte dissociates partially

Non-electrolyte doesn’t form ions (like sugar)

Dissolving a solid can be considered a two-step process of bond breaking and bond formation.

Bond Breaking: Dissolving a solid involves breaking bonds as the ions separate and the lattice is broken down (Coulomb’s law)

Bond Forming: Once the ions are separated, bonds are formed between the ions and solvent molecules, a process called solvation (or hydration if the solvent is water)

an ion by itself cannot be classifies as soluble or insoluble