Whole 2

• What is the oxidation number for combined 02?

  -2
• Calculate mass number

  (isotope number x abundance)/100
• Moles=

  Mass / Mr
• Calculating with moles

  1. Balance equation

  2. Calculate moles

  3. Ratio

  4. Calculate the mass, volume, concentration, etc.
• Limiting Factor

  The larger amount of moles
• Percentage Yield

  actual yield(mol)/theoretical yield(mol) x 100
• Atom economy

  (Molecular mass of desired products/ Molecular mass of all products) x 100
• Gas calculations

  mol=vol(dm3)/24
• Concentration=

  moles/volume
• Ideal gas equation

  PV=nRT
• Calculating empirical formula

  Pretend that you have a 100g sample.

  That is, change % to grams.

  Convert the grams to moles for each element.

  Divide each number by the smallest number.

  Multiply the result(if needed) to get rid of any fractions.
• Calculating water of crystallisation

  mass of hydrated- mass of sulfate= mass of water

  find moles of sulphate and water

  ratio the moles
• What is an isotope?

  atoms of the same element with the same number of protons but different number of neutrons
• Atomic Structure

  Electron on outer shell, neutron and proton in center, nuclei.
• Relative isotopic mass

  The mass of an atom of an isotope compared with one-twelfth of the mass of an atom of carbon-12.
• Relative atomic mass

  The weighted mean mass of an atom of an element compared with one-twelfth of the mass of an atom of carbon-12.
• Mole


  the SI base unit used to measure the amount of a substance
• Avogardos constant

  6.02 x 10^23 particles
• Empirical formula

  the simplest whole number ratio of atoms of each element present in a compound
• molecular formula

  The number and type of atoms in each element of a molecule
• Anhydrous


  without water
• Hydrated

  with water
• Water of crystallisation

  Water molecules that form an essential part of the crystalline structure of a compound
• Strong acid

  an acid that ionizes completely in aqueous solution
• Strong base

  A base that dissociates completely into ions in solution.
• Weak acid

  an acid that is only slightly ionized in aqueous solution
• Weak base

  A base that does not dissociate completely into ions in solution.
• Alkali

  A base that dissolves in water
• What is the oxidation number for an uncombined element?


  0
• What is the oxidation number for combined H2?

  +1
• What is the oxidation number for combined F2?

  -1
• What is the oxidation number for 02 when combined with F2?

  +2
• What is the oxidation number for O2 in a peroxide?

  -1
• Roman numerals as oxidation numbers


  Used when the compound my have different oxidation numbers
• Oxidation

  loss of electrons, oxidation number increases
• Reduction

  gain of electrons, oxidation number decreases
• Oxidation number

  Positive or negative number that indicates how many electrons an atom has gained, lost, or shared to become stable
• 1st shell

  2nd shell

  3rd shell

  4th shell

  2

  8

  18

  32
• s orbital

  spherical, 2 electrons
• p orbital

  dumbbell, 6 electrons