(a) List two substances that can be used in the laboratory to (i) dry hydrogen;...
(a) List two substances that can be used in the laboratory to
(i) dry hydrogen;
(ii) remove carbon (IV) oxide from a sample of air;
(iii) convert hot copper (II) oxide to copper;
(iv) prepare zinc chloride by the action of dilute HCI.
(b)(i) Name two alloys which contain lead.
(ii) State and explain what is observed on bubbling H\(_2\)S into a solution of Pb(NO)\(_2\).
(iii) A metal M exists as a silvery white solid at temperatures above 18°C and as a grey solid below 18°C.
I. name the phenomenon exhibited by M.
II. What term is used to describe the temperature given as 18°C in this case?
(c)(i) Write an equation for the action of heat on each of the following compounds:
I. AgNO\(_3\)
II. (NH4)\(_2\)CO\(_3\).
(ii) Copy and complete the table below
Metal | Name of main ore | Method of extraction | One major use Haematite |
— | Haematite | — | — |
— | — | Electrolysis of molten oxide | — |
Explanation
(a)(i) Fused calcium chloride and concentrated tetraoxosulphate (VI) acid.
(ii) Ca(OH)\(_2\), NaOH.
(iii) Hydrogen and carbon (II) oxide
(iv) Zn metals, zinc trioxocarbonate
(IV), zinc oxides.
(b)(i) Soft solder for welding and plumbing and type metal for printing.
(ii) a black precipitate of PbS\(_{(s)}\) is deposited
(iii)(i) Polymorphism
(ii) Transition temperature
(c)(i) 2AgNO\(_{3(s)}\) --> 2Ag\(_{(s)}\) + O\(_2\) + 2NO\(_{2}\).
Lustrous Brown white
(ii) NH\(_4\)CO\(_3\) -> 2NH\(_3\) + CO\(_2\) + H\(_2\)O.
(iii)
Metal | Name of main ore | Method of extraction | One major use Iron |
| Iron | Haematite | Reaction process | Constfuction of vehicles |
Aluminium | Bauxite | Electrolysis of molten oxide | cables, paints, cooking utensils |