reactions with acid/bases

• why do some aluminiumoxide bonds have covalent character?

  aluminium cations are small ions as their atomic radius is small, their cation is also stronger and more positive which distorts the electron cloud and changes the shape to a more covalent one
• what oxides react with acids?

  Na2o , mgo and al2o3
• what oxides react with bases?

  Al2O3, SiO2 , P4O10 ,SO2 and SO3
• what is the word equation for when a base + acid reacts?

  base + acid → water + salt
• why can aluminium react with both acids and bases

  because its amphoteric
• SiO2 reaction with bases?

  SiO2 acts as a weak acid

  it reacts with hot, concentrated sodiumhydroxide and produces sodiumsilicate which forms a colourless solution
• whats the equation for SiO2 + Naoh (balanced) with state symbols

  SiO2(s)+2NaOH(aq)→NaSiO3 (aq) +H20(l)
• how is SiO2 removed from iron?

  SiO2 is an impurity in the form of sand,

  its removed using limestone (CaCO3) in a burn furnace, the limestone decomposes into liquid quicklime (CaCO) and Co2

  the CaCO is known as liquid slag and reacts with the SiO2 to produce CaSiO3 (l)
• write down the two reactions that occur when Sio2 is removed as an impurity

  CaCO3(l) → CaCO(l) + CO2(g)

  CaCO (l)+ SiO2(s)→CaSiO3(l)
• how does phosphorus (v) oxide react with sodiumhydroxide? ( write equations and explain)

  P4O10 (aq) + 12 NaOH → 4Na3Po4 + 6H2O

  the phosphorus oxide reacts with water as it reacts with water vigorously, to produce phosphuric acid

  P4O10 + 6H20 → 4H3PO4

  then phosphuric acid disossiates in 3 stages as it reacts with naoh

  H3PO4 + NaOH → NaH2PO4 + H2O

  NaH2PO4 +NaOH → Na2HPO4 + H2O

  Na2HPo4 + NaOH → Na3PO4 + h2o

  then write the overall equation:

  3H3PO4 + 3NaOH →3H2o + Na3PO4
• write down the equations for the reaction of so2 reacting with sodiumhydroxide?


  So2(g) + NaOH(aq)→NaSO3

  NaSO3 +NaOh(aq) →Na2SO3 +H2O
• write down the equations/steps for when sulfurtrioxide reacts with NaOH

  again like phosphorus(v)oxide, SO3 reacts vigrouously with water, so

  SO3 + NaOH →H2O + Na2SO4

  then sodiumsulfate reacts with the water

  Na2SO4 + H20 → H2SO4

  then it disociates into a sulphate ion

  H2SO4 + NaOH → NaHSO4 + H2O

  NaHSO4 + NaOH → Na2SO4 + h2o

  then the overall equation
• write an equation for aluminiumoxide reacting with sulfuric acid aswell as the ionic equation?

  Al2O3 + 3H2SO4 → Al2(so3)4 + 3H20

  Al2O3 + 6H+ → 2Al+3 + 3H20
• write the equation of aluminiumoxide reacting sodium hydroxide

  Al2O3(s) + 2NaOH(aq) + 3H2O(l) → 2NaAl(OH)4(aq)