Redox

• The change in oxidation number identifies whether or not a substance has undergone oxidation or reduction
• Roman numerals are used to indicate the oxidation number of metals that may have different oxidation states in compounds
• Rules for Oxidation Numbers:

  • all elements in their natural state have the oxidation number of 0
  • oxidation numbers in a compound add up to 0
  • oxidation numbers of the components in an ion add up to the charge on that ion

  Order of Priority:

  1. elements in group 1, 2, & 3, respectively
  2. fluorine is -1
  3. hydrogen is usually +1
  4. oxygen is usually -2
  5. chlorine is usually -1
• ions with names ending in -ate contain oxygen
• What is the formula for carbon monoxide?

  CO
• What is the formula for methane?

  CH4
• What is the formula for nitrogen monoxide?

  NO
• What is the formula for nitrogen dioxide?

  NO2
• What is the formula for sulfuric acid?

  H2SO4
• What is the formula for ammonia?

  NH3
• What is the formula for nitrogen?

  N2
• What is the formula for oxygen?

  O2
• What is the formula for phosphorus?

  P4
• What is the formula for hydrogen?

  H2
• All of group 7 elements are diatomic molecules
• What is the formula for an ammonium ion?

  NH4+
• What is the formula for a carbonate ion?

  $CO3^2-$
• Define Redox:

  A reaction where both oxidation and reduction take place as one element is oxidised, donating its electrons to the other element that is reduced
• The oxidising agent becomes reduced because it gains electrons, decreasing its oxidation number
• The reducing agent becomes oxidised because it loses electrons, increasing its oxidation number
• Give the equation for the oxidising agent:

  $x^+$$+$$e^- -> x$
• Give the equation for the reducing agent:

  $x -> x^+$$+$$e^-$
• Define Disproportionation:

  a reaction in which the same element is both reduced and oxidised
• NH3 is an alkaline gas
• The formula for ammonium nitrate:

  NH4NO3
• Burning a substance means adding oxygen to it
• Formula for hydrogen carbonate:

  HCO3-
• Formula for Phosphoric Acid:

  H3PO4
• Formula for Phosphate ion:

  $PO4^3-$
• The empirical and molecular formula can be the same
• Percentages in empirical formula calculations all add up to 100%
• Using PV=nRT involving density:

  $gm^3$use v= 1 $m^3$

  $gdm^3$use v= 1 x 10^-3 $m^3$

  $gcm^3$use v= 1 x 10^-6 $m^3$
• Define a Monoprotic Acid:

  an acid that donates only one proton (H+)

  There's a 1 : 1 ratio; acid to base
• Define a Diprotic Acid:

  an acid that donates two protons (H+)

  There's a 1 : 2 ratio, acid to base
• Define a Triprotic Acid:

  an acid that donates 3 protons (H+)

  There's a 1 : 3 ratio, acid to base
• Give three examples of a monoprotic acid:

  • HCl
  • HNO3
  • CH3COOH
• Give three examples of a diprotic acid:

  • H2SO4
  • H2CO3
  • H2S
• Give an example of a triprotic acid:

  • H3PO4
• What kind of reagent is this equation for: $x -> x^+$$+$$e^-$ 


  reducing
• What kind of reagent is this equation for: $x^+$$+$$e^- -> x$


  oxidising