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 C2 2 Structure, Properties & Uses of Substances C2 3 Quantitative Chemistry & Analysis C2 4 Rates of Reaction C2 5 Exothermic and Endothermic Reactions C2 6 Acids, Bases and Salts C2 7 Electrolysis Foundation Questions - http://d416847d.exampro.net Standard Questions - http://1c3278f2.exampro.net Higher Questions http://ce300923.exampro.net Foundation Questions - http://a754b9fd.exampro.net Standard Questions - http://ebe97493.exampro.net Higher Questions http://63679610.exampro.net Foundation Questions - http://3e919235.exampro.net Standard Questions - http://5664e254.exampro.net Higher Questions http://af67f3cf.exampro.net Foundation Questions - http://5e3bb7fd.exampro.net Standard Questions - http://a20362e9.exampro.net Higher Questions http://2d12b53d.exampro.net Foundation Questions - http://6b44e863.exampro.net Standard Questions - http://f51b185e.exampro.net Higher Questions http://22ce4fb4.exampro.net Foundation Questions - http://5770cd46.exampro.net Standard Questions - http://a9a4619e.exampro.net Higher Questions http://b3c936bf.exampro.net 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