Ch 8 Acids and Bases

• What are the ions produced in ethanoic acid ( CH2COOH )


  H+ (aq) + CH3COO- (aq)
• What are the ions produced in hydrochloric acid ( HCl )


  H+ (aq) + Cl- (aq)
• What are the ions produced in nitric acid ( HNO3)


  H+ (aq) + NO3- (aq)
• What are the ions produced in sulfuric acid ( H2SO4 )


  2H+ (aq) + SO4 2- (aq)
• What happens when you put water onto solid acid?

  acid dissolves

  -> acid molecules ionise / dissociate

  -> produces H+ ions
• H+ ion is mainly responsible for the behaviour of acids
• What happens when you put blue litmus paper into solid acid?

  No change happens
• What is an acid?

  All acids are substances that produces hydrogen ions, H+, in aqueous solutions
• What are the properties of acids?

  Have sour taste

  Produce ions when dissolved in water

  -> allow resulting aqueous solution to conduct electricity

  Turn blue litmus paper red

  React with reactive metals

  React with bases (metal oxides and hydroxides)

  React with carbonates
• What is the equation for acids reacting with reactive metals?

  metal + acid -> salt + hydrogen
• What are salts called from acid reactions?

  sulfuric acid -> sulfates

  nitric acid -> nitrates

  hydrochloric acid -> chlorides
• How do you test for hydrogen gas?

  place a burning splint at the mouth of the test tube

  hydrogen gas extinguishes burning splint with a 'pop' sound
• What are unreactive metals in acids?

  copper (for weak acids)

  silver

  gold
• What happens when lead is put in acid?

  Initial reaction

  -> produces layer of lead (II) chloride / lead (II) sulfate

  -> layer is insoluble in water, quickly forming a coating around the metal

  coating protects metal from further reaction
• What is the equation for base + acid? (neutralisation)


  base + acid -> salt + water
• What is the equation for acid + carbonate?

  carbonate + acid -> salt + water + carbon dioxide
• What is the strength of acid?

  extent of ionisation of acid when dissolved
• What is a strong acid?

  completely ionised in aqueous solution
• What is are some examples of strong acids?

  Hydrochloric acid

  Sulfuric Acid

  Nitric acid
• What is a weak acid?

  acid that is only partially ionised in aqueous solution
• What does the strength of an acid depend on?

  degree of ionisation
• What does the concentration of an acid related to?

  number of acid molecules present in a given volume of water
• What are examples of weak acids?

  citric acid

  vinegar - ethanoic acid (CH3COOH)
• How is a strong acid different from a weak acid?

  Strong acid: completely ionised, produces more H+ ions

  weak acid: partially ionised, produces fewer H+ ions
• What pH is a strong acid?

  pH 1 or 2
• What is a base?

  any metal oxide / metal hydroxide

  contain either oxide ion (O 2-) / hydroxide ion (OH -)
• What are examples of common bases?

  sodium oxide ( Na2O )

  Zinc oxide ( ZnO )

  copper (II) oxide ( CuO )

  Magnesium hydroxide ( Mg(OH)2 )

  Aluminum hydroxide ( Al(OH)3 )
• What are alkalis?

  Alkalis are bases
• What are the ions produced from alkali? Sodium hydroxide ( NaOH )

  NaOH -> Na+ + OH-
• What are the ions produced from alkali? Potassium hydroxide ( KOH )

  KOH -> K+ + OH-
• What are the ions produced from alkali? calcium hydroxide ( Ca(OH)2 )

  Ca(OH)2 -> Ca2+ + OH-
• What are the ions produced from alkali? Ammonia ( NH3 )

  NH3 -> NH4+ + OH-
• What ions do aqueous solutions of alkali contain?

  OH- ions, metal ions
• Exception of NH3 of alkali-> no metal ions
• What is an example of a strong alkali?

  Sodium hydroxide (NaOH)

  -> fully ionised when dissolved in water
• What is an example of a weak alkali?

  Ammonia (NH3)

  -> partially ionised in water
• Bases can be strong/weak depending on the degree of ionisation
• What are the properties of alkalis?

  Taste bitter

  Feel slippery, soapy

  Dissolve in water to form solutions that conduct electricity

  Turn red litmus paper blue

  React with acids

  React with ammonium salts
• What happens in a neutralisation reaction?

  H+ (aq) + OH- (aq) -> H2O (l)

  H+ ion from acid

  OH- ion from alkali
• What is the equation of alkali and ammonium salt?

  Alkali + ammonium salt -> (by heating) salt + water + ammonia