Problems Review

Electrolysis & Redox half-reactions--

........... OXIDATION is a gain in oxidation state (valence) caused by a loss of electrons.

Cu ---> Cu+2 + 2e-

Al+3 + 3e- ---> Al

........... REDUCTION is a reduction in oxidation state caused by a gain of electrons.

Diffusion & Chromatography (show T-Shirt). Heavy MM moves more slowly and separates the colors in the ink.

Periodic Table & Goose Chart--

Tendencies, properties, etc.

DENSITY -- D = M/V, if M= 20g, and V= 5cm3 , D = M/V, so D= 20g/5cm3, = 4g/cm3

THE MOLE -- Get Moles by no. of particles, mass, volume, concentration, solutions (mol = ML) (L=ml/1000ml/L),

SOLUTIONS-- M = mol/L (L=ml/1000ml/L) . grams of solute = (M)(MM)(L)

Concentration of ions from a solute.

BaCl2(s) ---> Ba+2 + 2Cl-1 so [Cl-1] = 2[BaCl2]

PERCENTAGE COMPOSITION-- H2SO4

EMPIRICAL FORMULA (simplest)-- get mole ratios. e.g.. 31.9g Mg & 27.1g P.

MOLECULAR FORMULA-- Find it for benzene, MM= 78 amu & empirical formula is CH.

MASS NUMBER, ISOTOPES, ATOMIC MASS, MOLECULAR MASS

EQUILIBRIUM CONSTANT is the ratio of the [products] / [reactants]. In 2A + B ---> 3C + D

Keq = [C]3 [D] / [A]2 [B] , [ ] is the concentration in M. M = mol/L. L = ml/1000ml/L

Omit the concentrations of solids and liquid water (they have constant concentrations).

EQUILIBRIUM CONSTANT for Water, Kw = 1 X 10-14 H2O(l) <---> H+1(aq) + OH-1(aq) so

1 X 10-14 = (x)(x), and therefore in pure water, [H+1] & [OH-1] = 1 X 10-7 M.

BOND ANGLES-- Linear, Bent, Trigonal, Tetrahedral.

WARMING CURVE-- Warm Solid, Melting, Warm Liquid, Boiling, Warm Vapor.

 The pH SCALE is an abbreviation for the exponents of the [H+1] ions for solutions less than 1 M.

Because the pH numbers are exponents, a change of one pH is a ten-fold change in concentration!

WRITING and BALANCING EQUATIONS BY TRIAL AND ERROR-- Zn + HCl --->

The GAS LAWS: K = oC + 273o.

PV = nRT or PV/T = P’V’/T’

Standard Temp & Press. = 273 K and 760 mm (or 101.3 kPa).

PARTIAL PRESSURE: When a gas is collected over water, P(gas) = P(atm.) - P(water vapor)

MASS-MASS PROBS.-- 3H2 + N2 ---> 2NH3 Find grams of H2 to make 5 mol of NH3 .

  • MASS-VOLUME PROBS.-- 3H2 + N2 ---> 2NH3 Find how many liters of H2 are formed.
  • ACTIVATION ENERGY CURVES--
  • HEAT ENERGY-- DH = mcDt for H2O c= 4.18 j/g.Co (1 cal/g.Co)
  • Avogadro’s Law & examples.

    Balancing with fractions: C2H6 + 7/2 O2 ---> 2CO2 + 3H2O

    Acid + Carbonate:

  • 2HCl + Na2CO3 ---> 2NaCl + H2CO3

    H2CO3 ---> H2O + CO2

    • Acid Rain...

    SO2 + H2O ---> with oxygen ---> H2SO4

    NO2 + H2O ---> with oxygen ---> HNO3

    CO2 + H2O ---> with oxygen ---> H2CO3

    OZONE Pollution...

    Hydrocarbons from fuel + NOx and sunlight UV give ozone (poisonous).

    Results of Acid Rain... Kills plants, animals, erodes structures.

    Boom-- Show video 535 Sun, City, and Smog (25min).

      G o o d L u c k!