Name: __________________

C2 Revision Pack (Please keep this pack with you) Follow all the steps below...

1) Practice all the maths and ‘working scientifically’ questions – PRACTICE ALL THESE QUESTIONS!

Maths and Science Skills Questions

Foundation Questions - http://NUCOWUB.exampro.net Standard Questions – http://DUAUIEJ.exampro.net Higher Questions - http://AOKIOED.exampro.net

2) Practice Quiz – short answer questions (included in this pack)

3) Practice QWC questions – long answer questions (included in this pack)

4) Practice all the Popplet questions

C2 1 Structure and Bonding

Foundation Questions - http://D416847D.exampro.net Standard Questions - http://1C3278F2.exampro.net Higher Questions – http://CE300923.exampro.net

C2 2 Structure, Properties & Uses of Substances

Foundation Questions - http://A754B9FD.exampro.net Standard Questions - http://EBE97493.exampro.net Higher Questions – http://63679610.exampro.net

C2 3 Quantitative Chemistry & Analysis

Foundation Questions - http://3E919235.exampro.net Standard Questions - http://5664E254.exampro.net Higher Questions – http://AF67F3CF.exampro.net

C2 4 Rates of Reaction

Foundation Questions - http://5E3BB7FD.exampro.net Standard Questions - http://A20362E9.exampro.net Higher Questions – http://2D12B53D.exampro.net

C2 5 Exothermic and Endothermic Reactions

Foundation Questions - http://6B44E863.exampro.net Standard Questions - http://F51B185E.exampro.net Higher Questions – http://22CE4FB4.exampro.net

C2 6 Acids, Bases and Salts

Foundation Questions - http://5770CD46.exampro.net Standard Questions - http://A9A4619E.exampro.net Higher Questions – http://B3C936BF.exampro.net

C2 7 Electrolysis

Foundation Questions - http://2976C355.exampro.net Standard Questions - http://648C3C7E.exampro.net Higher Questions – http://283F8A63.exampro.net

Our Predictions: Experiments! E.g. Rates of reaction experiments, making salts, electrolysis etc. If this comes up as a 6 mark question – DON’T FORGET

TO WRITE A RISK ASSESSMENT. Graphs – Drawing and interpreting - Practice the maths and ‘working scientifically’ questions above!

C2.3 Quantitative Chemistry & Analysis – Revise this whole topic a lot, e.g. empirical formula, mass calculations, Ions, isotopes Making salts Crystalisation Metallic bonding and linking the structure to the properties of metals Electrolysis and half equations Neutralisation, e.g. equation, ions Ionic vs covalent structures, e.g. structure, linking to properties, drawing bonding Diamond vs graphite, e.g. structure, linking to properties Alloys vs pure metals Gas chromatography and mass spectrometry Thermosetting vs thermosoftening polymers Collision theory and rates of reaction

Nanoparticles

PRACTICE QUIZ

1. Which ion makes ammonia solution alkaline? (1 mark)

OH ion/ hydroxide ion

2. Name the type of reaction between aqueous ammonia solution and an acid (1 mark)

Neutralisation/ exothermic

3. Name the acid needed to produce ammonium nitrate (1 mark)

Nitric acid

4. Write the formula of ammonium sulphate (1 mark)

(NH4)2SO4 (Two ammonium ions are needed to neutralise the 2- charge on the sulphate ion.)

5. Suggest a PH value for sulphuric acid solution (1 mark)

0-6.9 (7 is neutral, 8-14 is alkali)

6. Name the ion which makes sulphuric acid solution acidic (1 mark)

H+ ion / hydrogen ion

7. Why do some farmers put ammonium nitrate on their farmland? (1 mark)

To fertilise the soil and to help plants grow

8. Why should the start line on chromatography paper be drawn in pencil not ink? (1 mark)

ink dissolves in the solvent, graphite does not

9. Give 2 advantages of gas chromatography compared with paper chromatography. (2 marks)

rapid / quick

accurate

sensitive / detects very small quantities

10. What does gas chromatography do to the mixture of solvents? (1 mark)

separates

11. What information does mass spectrometry give? (1 mark)

identifies solvents / compounds / substances

12. What is an exothermic reaction? (1 mark)

gives out energy / heat

13. Why does a solution of sodium thiosulfate and dilute HCL go cloudy? ( 2Mrks)

Because sulphur forms (1) which is insoluble (1)

14. Increase in temp of hydrogen peroxide increases the rate of the reaction, why? (3 marks)

The particles have more energy so move faster (1) so particles collide more often (1) and more of

collisions are successful (1)

15. How does a gold atom (Au) become a gold ion (Au3+)? (2 marks)

It loses / transfers (1) 3 electrons (1)

16. Why is the positive electrode in the cell used up during electrolysis? (2 marks)

because the electrode reacts with oxygen (1) to form carbon dioxide (1)

17. Why do hydrogen ions move to the negative electrode? (1 mark)

because they are positively charged

18. How does a hydrogen ion change into a hydrogen atom?

gains one electron

19. How do you remove unreacted copper oxide in the preparation of copper sulphate crystals?

Filtration

20. Why does the catalyst work for a long time before it needs replacing?

It is not used up

21. Why wouldn’t thermosoftening polymers be suitable for packaging very hot food? (2 marks)

They would melt / have a low melting point (1)

There are weak intermolecular forcer / no cross links (1)

22. How can gas chromatography separate substances in a mixture of compounds? (3 marks)

Substances carried by gas (1)

Through column packed with solids (1)

At different speeds (1)

23. What information does the molecular ion peak give about the molecule? (1 mark)

(relative) molecular mass/ Mr

24. What happens when sodium atoms react iodine atoms to produce sodium iodide? (3 marks)

sodium atom loses electron and iodine atom gains (1) one electron (1) electrostatic attraction (1)

25. Why does sodium iodide solution conduct electricity? (1 mark)

Ions can move in the solution

26. What formed at negative electrode when sodium iodide solution is electrolysed? (2 marks)

Hydrogen is formed (1) because sodium is more reactive (1)

27. Explain why silicon dioxide is a suitable material for lining furnaces. (4 marks)

high melting point (1)

because a lot of energy needed to break bonds (1)

because it is covalent or has strong bonds (1)

and because it is a giant structure or a macromolecule or a lattice (1)

28. Explain why copper is a good conductor of electricity. (2 marks)

copper has delocalized electrons (1) which can move through the metal / structure (1)

29. why doesn’t electrolysis of solid potassium salts to produce potassium work? (2 marks)

Current couldn’t flow (1) because the ions couldn’t move (1)

30. Describe how potassium atoms are formed from potassium ions. (2 marks)

Gain (1) 1 electron (1)

31. Carbon dioxide has a very low boiling point, explain why (3 marks)

Carbon dioxide is simple molecular (1)

There are intermolecular forces between the molecules (1)

Small amount of energy is needed to separate molecules / intermolecular forces are weak (1)

32. Suggest three reasons why gold is still used in industrial processes. (3 marks)

Gold is the only catalyst for some reactions.

Catalysts are not used up

Improve speed of reaction

Only small quantities of catalyst needed

33. Why does an electrolyte contain cryolite? (2 marks)

Because it lowers the melting point of the aluminium oxide (1)

So less energy is needed to melt is (1)

34. Why is the positive electrode in the cell used up during electrolysis? (2 marks)

because the electrode reacts with oxygen (1) to form carbon dioxide (1)

35. Why are there two hydroxide ions for each calcium ion in the formula Ca(OH)2? (1 mark)

Because calcium is +2 and hydroxide is -1 / to make the compound neutral charge

36. What are nanoparticles? (1 marks)

particles of size 1-100 nm

37. Why is graphite softer than diamond? (4 marks)

Because the layers (of carbon atoms) in graphite can move / slide (1) this is because there are only weak

intermolecular forces or weak forces between layers (1) however, in diamond, each carbon atom is

(strongly / covalently) bonded to 4 others (1) so no carbon atoms able to move (1)

38. Explain why graphite conducts electricity but diamond does not (3 marks)

because graphite has delocalized, sea of electrons (1) which can carry charge / current (1) however,

diamond has no delocalised electrons (1)

39. Explain why alloys are harder than pure metals. (3 marks)

because atoms in alloy are different sizes

so layers distorted

and layers don’t slide or slide less easily

40. Describe the structure and bonding in diamond. (4 marks)

giant structure / lattice / macromolecule (1)

strong bonds between carbon atoms (1)

covalent bonds (1)

each carbon / atom forms 4 bonds (1)

QWC 6 MARK QUESTIONS

KEY POINTS TO INCLUDE IN YOUR ANSWER:

Aluminium oxide is melted / made liquid

Aluminium ions are attracted to the negative electrode

At the negative electrode aluminium is formed

At the negative electrode aluminium ions gain electrons

Oxide ions are attracted to the positive electrode

Oxygen is formed at the positive electrode or oxide

Oxide ions lose electrons

The oxygen reacts with carbon to make carbon dioxide at positive electrode

KEY POINTS TO INCLUDE IN YOUR ANSWER:

Each carbon is covalently bonded to three other carbon atoms

There are only weak forces of attraction between layers

Layers can slide over each other

One electron on each carbon is not used for bonding

There are free electrons / delocalised electrons that carry the electric charge

KEY POINTS TO INCLUDE IN YOUR ANSWER:

Chemistry points made in the response:

Sulfuric acid is heated in a beaker and copper oxide is added whilst stirring

Keep on adding the copper oxide until the copper oxide is in excess

Filter the mixture / Pour the mixture through a funnel and filter paper

Filtering will remove the excess copper oxide

Some of the solution is then evaporated / heated in an evaporating basin

The solution is allowed to crystallise / cool down

Risk assessment points made in the response:

Wear safety goggles – to protect eyes because sulfuric acid is corrosive / an irritant

Take care when heating – to protect against burns

Wash hands after the preparation – copper sulfate is harmful

Take care when handling glass apparatus – to protect against cuts

KEY POINTS TO INCLUDE IN YOUR ANSWER:

Carbon dioxide is a simple covalent molecule

The intermolecular forces between carbon dioxide molecules are weak

Only a small amount of energy is needed to overcome the weak intermolecular forces

REMEMBER IT IS NOT THE COVALENT BONDS THAT ARE WEAK!

KEY POINTS TO INCLUDE IN YOUR ANSWER:

One reagent in beaker (or similar)

Add (any named) indicator, e.g. universal indicator

Add other reagent

Swirl or mix

Add dropwise near end point

Stop addition at change of indicator colour, e.g. when universal indicator turns green = neutral

Note volume of reagent added

Repeat without indicator, adding same volume of reagent

Pour solution into basin / dish

Heat using Bunsen burner so most but not all of the water evaporates

Leave remaining solution to crystallise

KEY POINTS TO INCLUDE IN YOUR ANSWER:

Thermosoftening polymers are made up of long chains

They have no cross links

They have weak intermolecular forces between the chains

Only a small amount of heat energy is needed to break these weak intermolecular forces

KEY POINTS TO INCLUDE IN YOUR ANSWER:

In alloys...

Atoms are different sizes

This distorts the layers

Layers cannot slide over each other

This makes them hard

In pure metals...

Atoms are all the same size

This means they form neat layers

Layers can easily slide over each other

This makes them soft

KEY POINTS TO INCLUDE IN YOUR ANSWER:

Diamond has a giant structure / lattice structure / is a macromolecule

Diamond has strong covalent bonds between atoms

Each carbon atom in diamond forms 4 covalent bonds

KEY POINTS TO INCLUDE IN YOUR ANSWER:

Add magnesium to acid

Dependant variable (measure) could be: (PICK ONLY ONE)

o Time for reaction

o Counting bubbles released

o Measuring the volume of gas released

Independent variable (change) could be: (PICK ONLY ONE)

o Concentration of acid

o Volume of acid

Control variables (keep the same) make it a fair test. They could be:

o Amount / mass / length / size of the magnesium

o Concentration / Volume of acid

o Try to think of at least three – make sure they are not your dependent/independent variable!

KEY POINTS TO INCLUDE IN YOUR ANSWER:

One magnesium atom reacts with two iodine atoms

Magnesium loses 2 electrons ...it then becomes a magnesium ion

Each iodine atom gains 1 electron ...it then becomes an iodide ion

Magnesium forms a positive ion

Iodine forms a negative ion

Oppositely charged ions attract

This forms a giant structure / lattice

KEY POINTS TO INCLUDE IN YOUR ANSWER:

Chlorine (In the exam it could be any other simple molecule but the mark scheme is always the

same - water, hydrogen, ammonia, methane, carbon dioxide, oxygen etc.):

Covalent bonds between atoms

Forms a simple molecule

Weak intermolecular forces between molecules (NOT WEAK COVALENT BONDS)

Only a small amount of energy needed to overcome weak intermolecular forces

This means it has a low boiling point and is a gas at room temperature

Sodium Chloride (In the exam it could be any other ionic substance but the mark scheme is

always the same – any group 1/2 metal bonded to a group 7/8 non-metal):

Ionic bonds between atoms

Strong electrostatic forces in all directions between oppositely charged ions

Forms a giant lattice

Large amount of energy needed to break these ionic bonds

This means it has a high boiling point and is a solid at room temperature

KEY POINTS TO INCLUDE IN YOUR ANSWER:

Advantages of using hydrogen:

There are renewable ways of producing hydrogen, e.g. electrolysis of water.

Combustion of hydrogen only produces water

Combustion of hydrogen does not produce carbon dioxide / not contribute to climate change

Combustion of hydrogen does not produce any particulates

Combustion of hydrogen does not contribute to global dimming

Petrol requires much more oxygen to burn so incomplete combustion is possible

Incomplete combustion of petrol produces carbon monoxide

Petrol comes from a non-renewable source

Disadvantages of using hydrogen:

Hydrogen has to be stored at high pressure and there is a risk of explosion

Hydrogen is a gas and this makes it difficult to store

Hydrogen produces much less energy and this means you need to refuel more often

Most methods of producing hydrogen need fossil fuels

KEY POINTS TO INCLUDE IN YOUR ANSWER:

Level 3 (5−6 marks) = There are statements about the results with at least one link and an attempt

at an explanation.

Statements

Concentration of copper sulfate increases

Temperature change increases

There is an anomalous result

The temperature change levels off

Reaction is exothermic

Linked Statements

Temperature change increases as concentration of copper sulfate increases

The temperature change increases, and then remains constant

After experiment 7 the temperature change remains constant

Statements including data

The trend changes at experiment 7

Experiment 3 is anomalous

Attempted Explanation

Temperature change increases because rate increases

Temperature change levels off because the reaction is complete

Explanation

As more copper sulfate reacts, more heat energy is given off

Once copper sulfate is in excess, no further heat energy produced

KEY POINTS TO INCLUDE IN YOUR ANSWER:

Level 3 (5−6 marks) = Correct statements about the effect of at least one condition on rate and yield and

at least one correct statement about compromise conditions.

Temperature

a higher temperature gives a lower yield

a higher temperature gives a faster rate

Pressure

a higher pressure gives a higher yield

increase in yield gets less as pressure increases

a higher pressure gives a faster rate

increase in rate increases as pressure increases

Catalyst

using a catalyst speeds up reaction

catalysts allow a lower temperature to be used and so save energy / reduce energy costs

Compromise

a higher pressure gives a greater yield but increases costs / (safety) risks

a high pressure gives a faster rate but increases costs / risks

a high temperature makes reaction faster but reduces yield

a catalyst makes reaction faster so a lower temperature can be used which will increase the yield

KEY POINTS TO INCLUDE IN YOUR ANSWER:

Level 3 (5−6 marks) = There is a well organised description of a laboratory procedure for obtaining

magnesium chloride that can be followed by another person. The answer must include a way of ensuring

the hydrochloric acid is fully reacted and a method of obtaining magnesium chloride crystals.

Put hydrochloric acid in beaker (or similar)

Add small pieces of magnesium ribbon until magnesium is in excess

Filter the excess magnesium using filter paper and funnel

Pour the solution into evaporating dish

Heat using Bunsen burner to evaporate sum but not all the water

Leave to crystallise while the rest of the water evaporates

Pat the crystals dry using filter paper