ZnO(s) + 2OH-(aq) + Zn(OH)2- H2O(l) → ZnO(s) + 2OH2- (aq) ZnO2- + H2O (l) → (b) Amphoterism 1 6. (a) B & D; 1 b) 4 1 7. Yellow solid melts to orange. 1 A grey residue is formed/Lead (II) oxide will be residue and change to lead which is silvery balls of residue; colourless droplets on cooler parts ; of the tube 1 8. (i) Graphite has a free delocalised electrons which is free to move and therefore make it a conductor of electricity 1 (ii) Molten lead (II) chloride is charged (Pb2+ and Cl(-) / conduct by increment of ions, When connected to electricity in the ions. When connected to electricity by the ions will move and transport electrons so conduct electricity). 1 (i) M 1 K (ii) 1 (iii) a) Simple molecular 1 b) Covalent bonds1 10. (a) - Crush the roses with suitable solvent (methyl/ethanol/propanol) 1 - Filter to obtain pigments / decant suck with a dropper1 (b) Add the pigments to an acid and base separately1 and state colour change red and green respectively. 1 Impure 11. (a) 1mk It condensed and freezed 1mk over arrange of temperatures Melting point/boiling Rej: point Particles of the substance in gaseous form are losing kinetic ½mk and come closer to one another, developing stronger interparticle forces of attraction. ½mk 12. (a) Weak alkali is the one that does not ionize completely in solution /less OH- ions √½mk while strong alkali is the one that undergoes complete ionization / many OH- ions ½mk √ Z, (b) (i) 1 (ii) M 1 13. Add water to the mixture Water mixes with the ethanol and forms the lower layer while upper layer is pentane.
ZnO(s) + 2OH-(aq) + H2O(l) → Zn(OH)2- ZnO(s) + 2OH2- (aq) → ZnO2- + H2O (l) (b) Amphoterism 1 6. (a) B & D; 1 b) 4 1 7. Yellow solid melts to orange. 1 A grey residue is formed/Lead (II) oxide will be residue and change to lead which is silvery balls of residue; colourless droplets on cooler parts ; of the tube 1 8. (i) Graphite has a free delocalised electrons which is free to move and therefore make it a conductor of electricity 1 (ii) Molten lead (II) chloride is charged (Pb2+ and Cl(-) / conduct by increment of ions, When connected to electricity in the ions. When connected to electricity by the ions will move and transport electrons so conduct electricity). 1 (i) M 1 (ii) K 1 (iii) a) Simple molecular 1 b) Covalent bonds1 10. (a) - Crush the roses with suitable solvent (methyl/ethanol/propanol) 1 - Filter to obtain pigments / decant suck with a dropper1 (b) Add the pigments to an acid and base separately1 and state colour change red and green respectively. 1 11. (a) Impure 1mk It condensed and freezed 1mk over arrange of temperatures Rej: Melting point/boiling point Particles of the substance in gaseous form are losing kinetic ½mk and come closer to one another, developing stronger interparticle forces of attraction. ½mk 12. (a) Weak alkali is the one that does not ionize completely in solution √½mk /less OH- ions while strong alkali is the one that undergoes complete ionization / many OH- ions √ ½mk (b) (i) Z, 1 (ii) M 1 13. Add water to the mixture Water mixes with the ethanol and forms the lower layer while upper layer is pentane.
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