Chemistry exam practice questions 3

Question 1

She was able to extract lead from lead oxide but not aluminum from aluminium oxide.
Explain the results of these experiments.

Answer 1

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.

Question 2

Complete this word equation for the reaction between lead oxide and carbon.

Answer 2

lead oxide + carbon → _______lead___________ + ____carbon dioxide________________

Question 3

what is an ore

Answer 3

compounds of metals found in rocks

Question 4

Some metals are obtained by removing oxygen from the metal oxide.
What name do we give to this chemical reaction?

Answer 4

reduction

Question 5

Name one metal which must be extracted from its melted ore by electrolysis rather than
by using carbon.

Answer 5

group 1 and 2 metals

Question 6

Zinc is extracted by removing oxygen from zinc oxide.

What name is given to a reaction in which oxygen is removed from a substance?

Answer 6

reduction

react with a metal word equation: zinc oxide+ carbon= carbon dioxide

Question 7

a) sodium + water → sodium hydroxide + _______________________ .
b) magnesium + ______________________________→ magnesium oxide.

Answer 7

• hydrogen-a

- oxygen-b

Question 8

Explain why gold is found mainly as the metal itself in the Earth.

Answer 8

because it is unreactive

Question 9

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.
____________________________________________

Answer 9

carbon is more reactive

Question 10

Predict the method of extraction used to obtain calcium from its ore and explain your
answer.

Answer 10

electrolysis because calcium is more reactive

Question 11

do question 6a on the sheet as you have to draw an arrow

Question 12

The formula for zinc oxide is ZnO. Write a balanced equation for the extraction of zinc in
the blast furnace.

Answer 12

zno+co– zn+co2

Question 13

Use information in the table to suggest why gold and platinum are very expensive metals.

Answer 13

because it has a very small percentage in the earth’s curst

Question 14

Use the reactivity series on the Data Sheet to suggest a metal that would reduce
aluminium ore.

Answer 14

potassium

Question 15

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?
________________________________________________________

Answer 15

high temperatures and carbon reacts with oxygen

Question 16

Suggest why aluminium is more expensive than iron.

Answer 16

large amount of electricity used

Question 17

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.

Answer 17

lead oxide + carbon – lead+ carbon dioxide

Question 18

what is reduction

Answer 18

oxygen removed

Question 19

What is the dependent variable in the investigation?

Answer 19

whether there was a reaction or not

Question 20

Give one observation the student could make that shows there is a reaction between zinc
and copper sulfate.

Answer 20

blue solution turns colourless

Question 21

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.

Answer 21

mass of metal powder- balance

volume of metal sulfate- measuring cylinder

Question 22

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.

Answer 22

magnesium, zinc and copper because it would not be safe

Question 23

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

Answer 23

_2__Fe2O3 + _3__C → __4_Fe + __3_CO2

Question 24

) Name the element used to reduce iron oxide

Answer 24

carbon

Question 25

A chemical reaction for the extraction of iron is: Fe2O3 + 3CO → 2Fe + 3CO2 (i) Complete the word equation for this chemical reaction. __

Answer 25

__iron oxide___________ + carbon monoxide → iron + __carbon dioxide ___________

Question 26

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

Answer 26

oxygen reacts with carbon and produces carbon dioxide

Question 27

Using plants to extract metals is called.........

Answer 27

phytomining

Question 28

Copper oxide reacts with carbon to produce copper and ...........................

Answer 28

carbon dioxide

Question 29

Copper is produced from copper sulfate solution by displacement using iron or by electrolysis. (i) Complete the word equation.

Answer 29

copper sulfate + iron --- __copper_________ + ___iron sulfate________

Question 30

Figure 2 shows the electrolysis of copper sulfate solution. | Why do copper ions go to the negative electrode?

Answer 30

to gain electron

Question 31

Suggest two reasons why copper should not be disposed of in landfill sites.

Answer 31

because copper is running out and copper is expensive

Question 32

Calcium carbonate decomposes at high temperatures. Complete the word equation for the decomposition of calcium carbonate. calcium carbonate _____________________ + _____________________

Answer 32

calcium carbonate --- ____calcium oxide _________________ + ___carbon dioxide __________________

Question 33

Carbon burns to produce carbon dioxide. The carbon dioxide produced reacts with more carbon to produce carbon monoxide. Balance the equation.

Answer 33

C(s) + CO2(g) __2___ CO(g)

Question 34

State three variables that the student must control to make his investigation a fair test

Answer 34

- concentration of the salt solution - form of metal - moles of metal

Question 35

Why is a line graph not a suitable way of showing the results?

Answer 35

no values between the metals (Gold and Silver)

Question 36

Use the results to work out which metal is the most reactive. Give a reason for your answer.

Answer 36

the most reactive metal magnesium | Reason biggest temperature change

Question 37

Explain why there was no temperature change when silver metal was added to the copper sulfate solution.

Answer 37

does not react because silver is below copper in the reactivity series

Question 38

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.

Answer 38

replace the copper sulfate with a metal less reactive than copper

Question 39

Give two variables the student should control so that the investigation is a fair test.

Answer 39

- concentration of dilute hydrochloric acid | - reacted for the same length of time

Question 40

One of the results for magnesium is anomalous. Which result is anomalous? Suggest one reason why this anomalous result was obtained.

Answer 40

Result ____magnesium test 2 (4.2 degrees Celsius)_________________________________________________________ ___________________________________________________________________ Reason ____lower mass of magnesium added ________________________________________________________ _________________________________________________________________

Question 41

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?

Answer 41

bubbles of gas , more bubbles seen with calcium than any other metals