Download Plastics and Modern Materials - Smithycroft Secondary School

Smithycroft Secondary
School
National 4 Chemistry Revision
Questions
Unit 3 - Chemistry in Society
Properties of Metals and Alloys
1. The grid below shows the names of some metals.
You can use your data book p7 to help you to find your answers.
(c) Identify the most reactive metal.
2. The Falkirk Wheel is a steel structure which carries boats from one level of the
canal to another.
(a) The Falkirk Wheel is painted to prevent rusting. How does painting prevent
rusting?
(b) Suggest another method to prevent rusting.
(c) Steel is an alloy. What does this term mean?
(d) Name another alloy.
(e) The table gives information on some steel alloys.
Carbon present in steel alloys (%)
0.1
0.2
0.3
0.4
0.5
Hardness (Units)
123
157
190
220
260
Predict the hardness of a steel containing 0.6% carbon
(f) Suggest one advantage of using steel compared to iron.
3. Naveed carried out an experiment to investigate the reaction of 3 metals with
sulphuric acid.
(a) Place the metals in order of reactivity (most reactive first).
(b) Name the gas that would be released in this reaction.
(c) Explain how you would test this gas to show what it is.
(d) Explain what you would see if Naveed used more concentrated sulphuric acid.
4. A teacher demonstrated the following experiment.
(a) The Universal indicator changed colour from green to purple. What does this tell
you about the solution?
(b) Why is lithium stored under oil?
5. Medical instruments can be made from a mixture of metals containing
76% titanium, 4% zirconium and the rest is other metals.
Label the pie chart to show the name and percentage for each part of the
mixture.
6. A student set up this experiment with clean nails in two dishes containing Ferroxyl
indicator to investigate rusting.
The diagram below shows the results of the experiment after 1 day.
(a) Write the symbol for the iron ion which turns Ferroxyl indicator blue.
(b) Explain why the magnesium attached to the iron nail prevents rusting.
7. Coating iron prevents rusting.
(a) Identify the coating used to galvanise iron.
(b) Identify the coating, which if scratched, would cause the iron to rust fastest.
8. A teacher demonstrated the experiment below.
Her results are shown below.
Metal
Zinc
Copper
Silver
Observation
Glowed brightly
Dull red glow
No reaction
(a) Predict what would happen if magnesium was used in this reaction.
You may wish to use p7 of the data book to help you.
(b) In a different experiment powdered zinc was used instead of a metal strip. How
would this affect the speed of the reaction?
(c) Silver is found uncombined in the earth’s crust. Name another metal that is
found uncombined in the earth’s crust.
You may wish to use p7 of the data book to help you.
9. Different methods can be used to prevent steel from rusting.
(a) How does tin-plating prevent steel from rusting?
(b) Name a metal which can be used to provide sacrificial protection to steel.
You may wish to use p7 of the data book to help you.
10. Steel can be used to make storage tanks for diesel. One method of protecting the
tanks from rusting is to connect magnesium to them.
(a) Name two substances that must be present for steel to rust.
(b) Name the type of protection offered by the magnesium.
(c) Suggest another method of protecting steel from rusting.
Electrochemistry
1. A battery is a number of cells joined together.
(a) Give one advantage of using a battery compared with mains electricity
(b) Why does a battery stop producing electricity after a while?
(c) A simple cell was set up using a lemon as shown below.
Use your data book p7 to help you with the next two questions.
(i) Draw an arrow on the wire to show the direction of electron flow.
(ii) Would the voltage be higher or lower if copper was used instead of nickel?
2. A student investigated how different metals affect the voltage in a simple cell.
The results are shown in the table.
Metal A
Magnesium
Tin
Voltage/V
2.7
0.5
(a) The student set up another cell using iron and copper.
Use your data book p7 to work out the voltage produced by this cell.
(b) Suggest one factor the student would have kept the same to make a fair
comparison.
3. A student set up the cell shown.
(a) On the wires, indicate the direction of electron flow using an arrow.
(b) Name a metal which could be used to replace the iron to give a smaller voltage.
You may wish to use p7 of the data book to help you.
(c) What is the purpose of the ion bridge?
4. The diagram on the next page shows a cell.
(a) Name the type of charged particle that flow through the wires.
(b) The voltage produced by the cell is 1.15V. Name a metal that could replace zinc
to give a higher voltage.
You may wish to use p7 of the data book to help you.
(c) Scientists at the University of St Andrews have developed a type of battery. It has
the advantage of being able to store up to 10 times more energy than some other
types of battery.
Suggest another advantage of using this type of battery.
Materials
1. PVC Production
In the manufacture of PVC, ethylene and chlorine are passed through a
catalyst chamber producing ethylene dichloride. The ethylene dichloride is
then cracked to produce vinyl chloride which undergoes polymerisation to
form the plastic poly(vinyl chloride), PVC.
(a) Use this information to complete the flow diagram.
(b) The systematic name for vinyl chloride is chloroethene.
(i) Show the structural formula for chloroethene.
(ii) What would be the systematic name for the polymer formed from chloroethene?
2, The plastic poly(propene) (PPE) has many uses.
(a) Name the monomer used to make poly(propene).
(b) Poly(propene) is non-biodegradable. Suggest why this might be an advantage.
(c) Poly(propene) can be used as a fibre in clothing. Laura set up the apparatus below
to investigate the strength of different fibres.
Her results table is shown here.
(i) How does the strength of the natural fibres compare to the strength of the
synthetic fibres?
(ii) She tested Fibre X and found it broke at 300g. Predict whether this fibre is natural
or synthetic.
3. Plastics have many uses. Perspex is used to make advertising signs.
Artificial limbs can be made from PVC. Polythene can be used to make
carrier bags and egg cartons can be made from polystyrene.
(a) Present this information as a table with suitable headings.
(b) Scientists have produced a plastic which is biodegradable. What does this word
mean?
(c) PVC softens when heated and can be easily shaped. What name is given to this
type of plastic?
(d) Name the monomer that is used to make poly(styrene).
(e) Name the type of chemical reaction that is used to make poly(styrene)
4. Here is an aluminium pan heating on a camping stove.
(a) The aluminium pot is strong, light and does not melt when heated. Name another
property of aluminium which makes it useful for cooking pots.
(b) The plastic handle also does not melt when heated. What name is given to this
type of plastic?
5. Some supermarkets no longer supply free polythene bags because they are
non-biodegradable and can cause environmental problems.
(a) What does non-biodegradable mean?
(b) Draw a section of polythene, showing 3 monomer units joined together.
6. Polystyrene is a plastic used in packaging. Scientists have found that starch, made
from sources such as barley, can be used to make a packaging material with similar
properties to polystyrene.
Suggest one advantage of this material compared to polystyrene.
Fertilisers
1. Nitric acid can be used to make fertilisers.
Explain why there has been a major increase in the use of fertilisers
over the last 100 years.
2. Ammonium nitrate is a synthetic fertiliser. It contains nitrogen which is essential
for plant growth.
(a) What is meant by the term ‘synthetic’?
(b) Name another essential element supplied by fertilisers.
(c) When ammonium nitrate is heated with calcium hydroxide, a colourless gas is
produced. The gas turns damp pH paper blue.
Name the colourless gas.
(d) Some compounds containing essential elements are unsuitable for use as
fertilisers.
Suggest a reason for this.
(e) Certain plants contain bacteria which can convert nitrogen from the air into
nitrogen compounds.
Which part of the plant contains these bacteria?
3. A teacher demonstrated an experiment to show how nitrogen dioxide is formed in
a petrol engine.
(a) Name the two gases that react to form nitrogen dioxide.
(b) Nitrogen dioxide can be formed naturally in air. What provides the high voltage
spark for this reaction?
(c) Nitrogen dioxide dissolves in water. Suggest a pH value for the resulting solution.
4. Ammonia can be used in industry to make nitric acid.
(a) Name this industrial process.
(b) The reaction is exothermic. What does this term mean?
(c) Which two elements are combined to form ammonia?
(d) Name the industrial process used to make ammonia from its elements.
Nuclear Chemistry
1. Nuclear fusion takes place in the stars.
(a) What is meant by ‘nuclear fusion’?
(b) Why is it important?
2. The radiation that is all around us is known as ‘background radiation’. Give a
source of
(a) artificial radiation
(b) natural radiation
Chemical Analysis
1. The grid shows the formulae for some compounds.
Use the table on p4 of your data book to answer the next two questions.
(a) Which compound would give a red flame colour?
(b) Which compound would give a green flame colour?
(c) Is flame testing an example of qualitative or quantitative analysis?
2. A student measured the pH of malt vinegar and some other substances. Her
results are shown in the table.
(a) Describe how the student would use universal indicator or pH paper to test the
substances.
(b) Malt vinegar is a mixture of ethanoic acid and water. Suggest a pH value for malt
vinegar.
3. Many ionic compounds are coloured.
Using the information in the table, state the colour of
(a) the chloride ion
(b) the dichromate ion
4. When aluminium iodide solution and lead nitrate solution are mixed together a
chemical reaction takes place.
(a) Name the solution formed in this reaction. Use your data book p5 to help you.
(b) Explain how you would remove the solid formed in the reaction.
Acknowledgements
SQA Chemistry General Level 2007-2013
Chemcord Revision Questions for National 5 Chemistry for Nuclear Chemistry only