Chem - Topic 8 /18

• Rxns with acids: Acids with metal...

  acid + metal  →  salt + hydrogen
• rxns with acids: Metals and oxides...

  acid + metal oxide →  salt + water
• rxns with acids: Metals and hydroxides

  acid + metal hydroxide →  salt + water
• Rxns with acids: Metals and carbonates

  acid + metal carbonate → salt + water + carbon dioxide
• rxns with acids: Metals and hydrogencarbonates


  acid + metal hydrogencarbonate → salt + water + carbon dioxide
• What is a neutralization rxn

  A neutralisation reaction is one in which an acid (pH <7) and a base/alkali (pH >7) react together to form water (pH = 7) and a salt
• Lewis acid


  an electron pair acceptor
• Lewis base


  Electron pair donor
• Bronsted -lowry acid


  proton donor
• bronzed-lowry basae


  proton acceptor
• For a strong acid and strong base titration, what is the pH of the equivalence point?

  7
• Increase in pH by 1 is equivalent to


  increase in [H+] by 10 folds.
• Water ionization equation is


  Kw = [H+][OH-] =1.0×10^−14
• For pure water 


  [H+] = [OH-]
• Strength of acids and bases are determined by

  the extent to which they ionize into their individual ions.
• Weak acids end with


  COOH or "oic"
• Ammonium is NH4+, it is a...

  a weak acid that is very weak.
• Ammonia is NH3, it is

  a weak base, but a strong weak base.
• Strong acids have -- conjugates.

  weak
• Amphoteric means


  a substance that can act like an acid or a base depending on the reaction.
• Amphiprotic means/ is 


  a kind of amphoteric substance that can either donate or accept a proton.
• How many type Sof acid-base titrations are there?

  4
• what does a buffer consist of

  A buffer consists of a weak acid and its conjugate base or a weak base and its conjugate acid
• when a buffer is formed..

   the buffer will resist changes in pH so the pH rises gradually as shown in the buffer region
• The half equivalence point is the stage of the titration at which

  exactly half the amount of weak acid has been neutralised
• at the half equivalence point, 


  • pKa = pH 
• the 1/2 equivalence point is considered the

  buffer region
• Acid - base indicators are

  weak acids or bases in which the undissociated and dissociated forms have different colours
• What is the end point of an indicator

  it is the pH at which it changes colour.
• an indicator changes colour when the pH is equal to

  Pka
• When choosing the indicator for an acid base titration

  we take teh pH at the equivalence point and find the suitable one on the data booklet
• What are Ka and Kb called?

  acid and base dissociation constants
• the larger the value of Ka

  the greater the degree of dissociation and the stronger the acid and hte higher hte concentration of [H3O+] at equilibrium
• the larger the value of Kb

  the larger the concentration of OH- @ equilibrium, and the stronger the base
• pH +pOH = 


  14.00 at 298k
• For a conjugate acid-base pair we have the following relationship: 


  Ka x Kb = Kw = 1.00 x 10 ^-14
• pKa = -log Ka what does Ka equal: like wise for pKb


  Ka= 10^-pKa
• pKa + pKb = 14 = pKw
• salt hydrolysis


  when a cation or an anion form a salt react with water to produce an acidic or basic solution
• what re the components of a buffer solution

  usually the conjugate acid-base pair of a weak acid.