04.28.2014- Oxidation-reduction reactions involve the transfer of electrons from 1 species to another.  we change the oxidation state- Most energy related reactions are redox reactions - Glucose + O2  CO2 + H2O + energy- Oxygen is a good oxidant…usually involved in combustion- Oxidation – loss of electrons- Reduction – gaining electrons- O.I.L. R.I.G.- We keep track of the elements by assigning oxidation numbers- General Rules - 1. Pure elements are 0, (Na, O2, He, Cl2, Li)- 2. Charge of a single atom = oxidation number (Na+ =1, Mg2+ =2)- 3. The sum of all oxidation numbers = total charge of molecule- Specific Rules - 1. Hydrogen: +1 with a nonmetal (HCl, HF, CH4); -1 with a metal or boron (LiH, BH3)- 2. Oxygen: -2 in most compounds (CO2, H2O, CO); -1 in peroxides- 3. Halogens: -1 usually, Can be different with O or other halogens above them; Fluorine is always -1- 4. Everything else is figured out by arithmetic- Example: Ammonium Nitrate = NH4NO3; H = +1 N = -3- What happens when we put Mg, Zn, and Cu in acid?- - React with acid, not water!- - Electrons flow from more active metals to less active metals- Activity Series - A metal higher in the series will displace an element below it in the series.- If a metal is above H2 on the series, it will react w/ acid to form Hydrogen gas- They put zinc on steel ships so seawater doesn’t corrode it04.30.2014- A properly balanced reaction means both mass and charge are balanced- We need to keep track of atoms and electrons- Sometimes the solvent is involved in the reaction- Another way to look at redox reactions is to separate them:- Fe2++ MnO4-  Fe3+ + Mn2+ (acidic solution)- 2 half reactions:- Fe2+  Fe3+ iron is oxidized- MnO4-  Mn2+ manganese is reduced- Because there is an O, we can add water on one side to balance it out- Balance H with H+- Use electrons to balance charges- For balancing in basic conditions, add OH- to get rid of H+  add equal numbers to bothsides05.02.2014- 1. FeCl3-  Cl = -1; Fe = +3- 2. NO2-  N = +4; O2 = -2- H2SO4-  H2 = +1; S = +6; O4 = -2- 2. Al + MnO4-  MnO2 + Al(OH)4-- - Al  Al(OH)4-- 4H2O +Al  Al(OH)4- + 4H+ +3e-- - MnO4-  MnO2- 4H+ + MnO4-  MnO2 +2H2O- 3e- + 4H+ +MnO4-  MnO2 + 2H2O- - 2H2O +Al + MnO4-  Al(OH)4- + MnO2- 3) Cl2  Cl- + ClO-- - Cl2  Cl-- 2e- +Cl2  2Cl- - Cl2  ClO-- 2H2O + Cl2  2ClO- + 4H+ + 2e-- 2H2O +2Cl2  2Cl- +2ClO- + 4H+- 4) NO2- +Al  NH3 + AlO2-- - NO2-  NH3- 7H+ + NO2-  NH3 + 2H2O- 6e- + 7H+ + NO2-  NH3 + 2H2O- - Al  AlO2-- 2H2O +Al  AlO2- + 4H+- 2(2H2O + Al  AlO2- + 4H+ +3e-)- OH- + H2O + 2Al + NO2-  NH3 +2AlO2-- 5) MnO4- + S2-  MnS + S- - 5(S2-  S + 2e-) 8H+ + S2- + MnO4-  MnS + 4H2O- 2(5e- + 8H+ + S2- + MnO4-  MnS + 4H2O)- 7S2- + 8H2O + 2MnO4-  5S + 2MnS + 16OH-- 6) CN- + MnO4-  CNO- + MnO2- 3(H2O + CN-  CNO- + 2H+ + 2e-)- 4H+ + MnO4-  MnO2 + 2H2O + 3e-- 2(4H+ + 3e- + MnO4-  MnO2 + 2H2O)- 3CN- + 2H+ + 2MnO4-  3CNO- + 2MnO2 + 2OH- 2CN- + H2O + 2MnO4-  3CNO- + 2MnO2 + 2OH-05.05.2014The Atmosphere an Pressure- The earth’s atmosphere is 50 km thick and is composed of:- 78% nitrogen, 21% oxygen, and trace gases: Ar, CO2, H2O, Ch4, etc…- The weight of these gases exert pressure because gravity pulls it down. - Pressure depends on:- location, temperature, weather- altitude- amount of air- Sea level vs. Mountain level- P sub gas = 0- Characteristics of gases:- - Highly compressible- - Thermally expandable- - Low viscosity (easy to pour)- - Low density - “Infinity miscible” – can mix together in any proportion- Pressure is force per unit area:- P = F/A- SI units: N/m^2  the Pascal (pa)- atm, mmHg, torr- Standard atmospheric pressure = 1 atm = 760 mm Hg- P = h x g x d- (h x g x d) = Force of hg in a cross-section- P = atmospheric pressure- h = height; g = gravity; d = density- For Mercury Barometers:- Sea Level = 1 atm = 760 mmHg- Units of Pressure and Converting - 1 atm = 760 mmHg = 760 torr = 14.7 psi- The volume of gas decreases when pressure is applied- Volume of gas decreases in cold and increases in hot- Volume of gas increases when you add more- Pressure goes up if you heat it up05.07.2014- Boyle’s Law: P1V1 = P2V2- Pressure down = Volume up- Pressure up = Volume down- T and n (# of moles) are constant- Charles’ Law: V1/T1 = V2/T2- Temp up = Volume up- Temp down = Volume down- V/T = constant- Temperature must always be in Kelvin- K = Celsius + 273.15- Avogadro’s Law: V1/n1 = V2/n2- moles up = volume up- moles down = volume down- V/n = constant- Amonton’s Law: P1/T1 = P2/T1- Temp up = pressure up- Temp down = Pressure down- P/T = constant- Convert to K- Keep track of variables that change- V (alpha) 1/P- V (alpha) T- V (alpha) n- P (alpha) T- PV/ nT = constant= R= the Gas constant- IDEAL GAS LAW: PV = nRT- P: pressure (atm)- V: volume (L)- n: moles- T: temperature (K)- R: 0.082057 (L x atm)/(mol x k)- 8.3145 I/Mol x k- Gas particles don’t attract or repel each other- Volume of gas particle is negligible compared to the container- An ideal gas is a collection of non-interacting point particles- Non-ideal: high pressure; low