HELP
1The first list below shows three metals. The most reactive metal is at the top and the least reactive metal is at the bottom. The second list shows some displacement reactions.
aMatch each metal in the first list to a correct statement about it from the second list. You can use each metal once, more than once or not at all.
bExplain why magnesium would displace all three of the metals in the list of metals from their solutions.
2Powdered magnesium reacts with lead oxide.
aCopy and complete the word equation shown below.
magnesium + lead oxide + → +
bThis reaction gets very hot. Copy and complete the sentence below:
The reaction between magnesium and lead oxide gets very hot because …
CORE
3Dave's dustbin is made from galvanised iron. This means that it is made from iron that has been coated with a thin layer of zinc.
aWhy is Dave's dustbin unlikely to go rusty, even if it is scratched and some of the iron is exposed to air and water?
bWrite a word equation to represent what would happen to Dave's bin if it was scratched and attacked by damp air. (Hint: Remember why zinc blocks are attached to ships.)
cExplain why coating the bin with a thin layer of copper would not be successful, if the bin was scratched?
diCopper sulphate solution is blue. Iron sulphate solution is pale green. Copper metal is pinkish-brown. Iron metal is shiny silver.
Describe what you would see happening, to the iron and to the solution, if a lot of powdered iron was added to a small amount of copper sulphate solution.
iiExplain why these changes would happen.
EXTENSION
4Sand contains silicon dioxide in a fairly pure form. The silicon needed for computer chips is made by reacting silicon dioxide with aluminium.
aiWhich is more reactive, the silicon or the aluminium?
iiExplain your answer.
bExplain why the temperature of the silicon that is made in this reaction is more than 500 °C.
cSuggest a reason why the fairly high cost of the silicon made by this reaction is not related to the cost of the silicon dioxide.
5A similar reaction is used, in a blast furnace, to extract iron from iron ore. One type of iron ore is haematite, which contains iron oxide. It is reacted with carbon. One of the products of the reaction turns limewater milky.
aWhich is the more reactive, the iron or the carbon?
bThe iron is produced as a liquid but its melting point is 1539 °C. What does this tell you about the energy changes during the reaction?
cWhat type of reaction is taking place in the blast furnace to extract the iron from the iron ore?
dWhat is the gas that is also produced?
© Harcourt Education Ltd 2004 Catalyst 3
This worksheet may have been altered from the original on the CD-ROM.