The diagram shows a portable apparatus used by a geology club to demonstrate the thermite reaction safely at a quarry education centre. A mixture of alumini...
Question 1 Report
The diagram shows a portable apparatus used by a geology club to demonstrate the thermite reaction safely at a quarry education centre. A mixture of aluminium powder and iron(III) oxide is placed in a ceramic crucible above a tray of dry sand. A magnesium ribbon is used as an ignition source. Once started, the reaction gives molten iron and aluminium oxide. It releases a large amount of heat, so it is not carried out in a normal school laboratory.
(a) Name the metal oxide in the starting mixture. [1]
(b) State which metal is more reactive, aluminium or iron. [1]
(c) Complete the word equation.
aluminium + iron(III) oxide → aluminium oxide + ............ [1]
(d) Explain why aluminium can remove oxygen from iron(III) oxide. [2]
(e) Give two observations expected after the reaction is started. [2]
(f) Write the balanced equation: Fe2O3 + 2Al → ............ + ............ [2]
(g) State one reason why dry sand is placed below the crucible. [1]
(h) Explain why magnesium ribbon is needed only to start the reaction. [1]
Answer Details
(a) The oxide is iron(III) oxide. [1]
(b) Aluminium is more reactive than iron. [1]
(c) aluminium + iron(III) oxide \(\rightarrow\) aluminium oxide + iron [1]
(d) Aluminium is more reactive than iron and has a stronger attraction for oxygen. It removes oxygen from iron(III) oxide, displacing iron from its oxide. [2]
(e) Two expected observations are bright light and intense heat. Molten iron, sparks, or white aluminium oxide are also acceptable. [2]
(f) \[\mathrm{Fe_2O_3 + 2Al \rightarrow 2Fe + Al_2O_3}\] [2]
(g) Dry sand contains the molten iron and prevents damage caused by the very hot product. [1]
(h) Magnesium supplies the activation energy to ignite the mixture. Once started, the thermite reaction is exothermic and releases enough heat to continue. [1]
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