Chemistry exam practice questions 3 Flashcards
She was able to extract lead from lead oxide but not aluminum from aluminium oxide.
Explain the results of these experiments.
carbon is above lead in the reactivity series and carbon is below aluminum in the reactivity series. Carbon can remove oxygen from lead oxide but cannot remove oxygen from aluminum oxide.
Complete this word equation for the reaction between lead oxide and carbon.
lead oxide + carbon → _______lead___________ + ____carbon dioxide________________
what is an ore
compounds of metals found in rocks
Some metals are obtained by removing oxygen from the metal oxide.
What name do we give to this chemical reaction?
reduction
Name one metal which must be extracted from its melted ore by electrolysis rather than
by using carbon.
group 1 and 2 metals
Zinc is extracted by removing oxygen from zinc oxide.
What name is given to a reaction in which oxygen is removed from a substance?
reduction
react with a metal word equation: zinc oxide+ carbon= carbon dioxide
a) sodium + water → sodium hydroxide + _______________________ .
b) magnesium + ______________________________→ magnesium oxide.
- hydrogen-a
- oxygen-b
Explain why gold is found mainly as the metal itself in the Earth.
because it is unreactive
One of the reactions involved in producing zinc is represented by this equation.
ZnO + C → Zn + CO
Explain why carbon can be used to extract zinc.
____________________________________________
carbon is more reactive
Predict the method of extraction used to obtain calcium from its ore and explain your
answer.
electrolysis because calcium is more reactive
do question 6a on the sheet as you have to draw an arrow
The formula for zinc oxide is ZnO. Write a balanced equation for the extraction of zinc in
the blast furnace.
zno+co– zn+co2
Use information in the table to suggest why gold and platinum are very expensive metals.
because it has a very small percentage in the earth’s curst
Use the reactivity series on the Data Sheet to suggest a metal that would reduce
aluminium ore.
potassium
Aluminium is made by the reduction of molten aluminium ore, using a very large amount of
electricity.
(i) How is iron ore reduced in a blast furnace to make iron?
________________________________________________________
high temperatures and carbon reacts with oxygen
Suggest why aluminium is more expensive than iron.
large amount of electricity used
One step in the manufacture of lead is the reduction of lead oxide with carbon. Lead and carbon
dioxide are the products of this reaction.
(a) Write a word equation for this reaction.
lead oxide + carbon – lead+ carbon dioxide
what is reduction
oxygen removed
What is the dependent variable in the investigation?
whether there was a reaction or not
Give one observation the student could make that shows there is a reaction between zinc
and copper sulfate.
blue solution turns colourless
The student used measuring instruments to measure some of the variables.
Draw one line from each variable to the measuring instrument used to measure the
variable.
mass of metal powder- balance
volume of metal sulfate- measuring cylinder
Use the results shown in table above to place zinc, copper and magnesium in order of
reactivity.
Most reactive _____________________
_____________________
Least reactive _____________________
(1)
(e) Suggest one reason why the student should not use sodium in this investigation.
magnesium, zinc and copper because it would not be safe
Iron is found in the Earth as iron oxide (Fe2O3).
Iron oxide is reduced to produce iron.
Balance the equation for the reaction.
___Fe2O3 + ___C → ___Fe + ___CO2
(1)
(h) Name the element used to reduce iron oxide
_2__Fe2O3 + _3__C → __4_Fe + __3_CO2
) Name the element used to reduce iron oxide
carbon
A chemical reaction for the extraction of iron is:
Fe2O3 + 3CO → 2Fe + 3CO2
(i) Complete the word equation for this chemical reaction.
__
__iron oxide___________ + carbon monoxide → iron + __carbon dioxide ___________
Cast iron contains about 4% carbon.
Cast iron is converted into low-carbon steels.
(i) Low-carbon steel is produced by blowing oxygen into molten cast iron.
Suggest how oxygen removes most of the carbon
oxygen reacts with carbon and produces carbon dioxide
Using plants to extract metals is called………
phytomining
Copper oxide reacts with carbon to produce copper and ………………………
carbon dioxide
Copper is produced from copper sulfate solution by displacement using iron or by
electrolysis.
(i) Complete the word equation.
copper sulfate + iron — __copper_________ + ___iron sulfate________
Figure 2 shows the electrolysis of copper sulfate solution.
Why do copper ions go to the negative electrode?
to gain electron
Suggest two reasons why copper should not be disposed of in landfill sites.
because copper is running out and copper is expensive
Calcium carbonate decomposes at high temperatures.
Complete the word equation for the decomposition of calcium carbonate.
calcium carbonate _____________________ +
_____________________
calcium carbonate — ____calcium oxide _________________ + ___carbon dioxide __________________
Carbon burns to produce carbon dioxide.
The carbon dioxide produced reacts with more carbon to produce carbon monoxide.
Balance the equation.
C(s) + CO2(g) __2___ CO(g)
State three variables that the student must control to make his investigation a fair test
- concentration of the salt solution
- form of metal
- moles of metal
Why is a line graph not a suitable way of showing the results?
no values between the metals (Gold and Silver)
Use the results to work out which metal is the most reactive.
Give a reason for your answer.
the most reactive metal magnesium
Reason biggest temperature change
Explain why there was no temperature change when silver metal was added to the
copper sulfate solution.
does not react because silver is below copper in the reactivity series
It is not possible to put all six metals in order of reactivity using these results.
Suggest how you could change the experiment to be able to put all six metals into
order of reactivity.
replace the copper sulfate with a metal less reactive than copper
Give two variables the student should control so that the investigation is a fair test.
- concentration of dilute hydrochloric acid
- reacted for the same length of time
One of the results for magnesium is anomalous.
Which result is anomalous?
Suggest one reason why this anomalous result was obtained.
Result ____magnesium test 2 (4.2 degrees Celsius)_________________________________________________________
___________________________________________________________________
Reason ____lower mass of magnesium added ________________________________________________________
_________________________________________________________________
The temperature rose when the metals were added to sulfuric acid.
Give one other observation that might be made when the metal was added to sulfuric acid.
How would this observation be different for the different metals?
bubbles of gas , more bubbles seen with calcium than any other metals
