C2 Chemistry

Additional Science

Key Recall Questions

*Cover up the answers, ask yourself a question (or get your partner to ask you), if you get it right then tick the chart, wrong put a cross. Keep practising until all columns are ticked! Key terms

Key Recall Answer Question 1. What is a A general word used by scientists to mean small part of matter (something) particle? 2. What is The smallest particle that can be recognized as an element. If you break an element into its smaller pieces you can no longer recognize that it is an element. an atom? 3. What is A substance that is composed of only one type of atom. an element?

4. What is a Substances which are together (in the same space) but not chemically joined. mixture? 5. What is a Substances in which atoms of two or more elements are chemically combined. compound? 6. What is a A word to describe atoms which are chemically joined together. These might be two of the same type of atoms (an element molecule) or two or more different types of atom (a compound molecule? molecule) 7. What are The substances which react together in a chemical reaction the reactants of a chemical reaction?

8. What are The substances which are produced as a result of a chemical reaction the products of a chemical reaction?

9. Why is it The arrows shows ‘reacts to make’ and signifies that the reactants have been chemically changed into products and cannot be (easily) reversed important to show chemical reactions with an arrow? 10. What Solid (s), Liquid (l), Gas (g) and Aqueous (aq) which means dissolved in water are the four state symbols used in chemical reactions and what do they mean?

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C2.1 Structure and bonding_1

Key Recall Answer Question 1. What is a Substances in which atoms of two or more elements are chemically combined. compound? 2. What are They transfer or share electrons in the highest occupied energy levels (shells) the two ways chemical bonds achieve the electronic structure of a noble gas? 3. What do Ions atoms become when they form chemical bonds by transferring electrons? 4. What Positive (+) charge do ions have when the atom which formed them lost an electron? 5. What Negative (-) charge do ions have when the atom which formed them gains an electron? 6. What +1 charge do ions have when they are formed from an element in group 1? 7. What -1 charge do ions have when they are formed from an element in group 7? 8. What +2 charge do ions have when they are formed from an element in group 2? 9. What -2 charge do ions have when they are formed from an element in group 6? 10. Which Group 0 (noble gases) group of elements do not form ions? Question Date: Date: Date: Date: Date: Date: Date:

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C2.1 Structure and bonding_2

Key Recall Answer Question 1. What The electron structure of a noble gas type of electron structure do ions have? 2. What are Alkali metals the elements in group 1 known as? 3. When A single positive charge they react with non- metals, what charge does the metal ion have in the ionic compound formed? 4. Can you Lithium, sodium, potassium, rubidium, caesium, francium (it is important that you at least know sodium is a group 1 element) name any elements in group 1? 5. What are Halogens the elements in group 7 known as? 6. When A single negative charge they react with alkali metals, what charge does the halide ion have in the ionic compound formed? 7. Can you Fluorine, chlorine, bromine, iodine, astatine (It is important that you at least know chlorine is a group 7 element) name any elements in group 7? 8. How are Ionic compounds are held together by strong electrostatic forces of attraction between oppositely charged ions. ionic compounds formed? 9. What is A structure formed as the result of all the electrostatic forces between ions attracting each other. an ionic lattice? 10. What is Sodium chloride the name of the ionic compound formed when sodium and chlorine form ions? Question Date: Date: Date: Date: Date: Date: Date:

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Key Recall Answer Question 1. What Covalent type of bonding is formed when atoms share electrons? 2. How Very strong strong are covalent bonds?

3. Can you Hydrogen (H2), Chlorine (Cl2), Oxygen (O2), Hydrochloric acid (HCl), Water (H2O), Ammonia (NH3) and Methane (CH name seven small covalent molecules and give their formula? 4. Can you Diamond, graphite and silicon dioxide. name three macromolec ules which have giant covalent structures? 5. What are They have low melting and boiling points (so are often gases) because the intermolecular forces (forces between molecules, not within) are weak so are easily broken the boiling points of small covalent molecules like and why? 6. Do simple They do not conduct electricity because the molecules do not have an overall electric charge. covalent molecules conduct electricity ad why/why not? 7. What is Metals are giant structures of atoms arranged in a regular pattern. They have positive metal ions with electrons between the ions holding them together with strong electrostatic attraction. the structure of a metal like? 8. What is They are ‘delocalised’ so are free to move about through the whole structure special about the electrons in a metal? 9. Name Potassium, sodium, magnesium, etc. some reactive metals 10. Name Gold, platinum, silver some unreactive metals Question Date: Date: Date: Date: Date: Date: Date:

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C2.2 How structure influences properties_1

Key Recall Answer Question 1. When a The weak intermolecular forces are broken (forces between the water molecules). small covalent molecule like water boils, what happens to it? 2. What is a An ionic compound with a regular structure in which there are strong electrostatic forces in all directions between oppositely charged ions giant ionic lattice? 3. What are They are high because the forces of attraction are strong, and there are many of them, so a great deal of energy is needed to break these bonds. the melting and boiling points of ionic compounds (lattices) like and why? 4. Do most Only when dissolved or melted as this means the charged ions are free to move and can therefore carry a current ionic compounds conduct electricity? 5. Which Diamond (Carbon), Graphite (Carbon) and sulicon dioxide (Sulphur and Oxygen or ‘silica’) chemicals are diamond, graphite and silicon dioxide made of? 6. What are They are very high because the covalent bonds between atoms are very strong the melting and boiling points of large covalent molecules like diamond, graphite and silicon dioxide like and why? 7. How are One carbon atom is covalently bonded to four other carbon atoms so diamond is very hard. the atoms in diamond arranged and which properties does this mean it has? 8. How are One carbon atom is covalently bonded to three other carbon atoms to form layers. This means there are delocalised electrons therefore the layers are free to slide over each other because there the atoms are no covalent bonds between them. This means graphite is soft, slippery and able to conduct electricity and heat (unlike diamond). and electrons in graphite arranged and which properties does this mean it has? 9. What are Fullerenes are hexagonal rings of carbon atoms. fullerenes? 10. What They can be used for drug delivery into the body, in lubricants, as catalysts, and in nanotubes for reinforcing materials (e.g. tennis rackets) can fullerenes be used for? Question Date: Date: Date: Date: Date: Date: Date:

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C2.2 How structure influences properties_2

Key Recall Answer Question 1. In terms Because they have delocalised electrons in their structures. of their structure, why do metals conduct heat and electricity? 2. What They are able to be bent and shaped. property do the layers in metals give them? 3. What are Metals which are usually made from two or more different metals. alloys? 4. Why are Because they have different sized atoms (due to the two or more different type of metal) so the layers are distorted and find it difficult to slide over each other. alloys harder than pure metals? 5. Can you Nitinol (used in dental braces), shape memory alloys can return to their original shape. name a shape memory alloy and describe what this term means? 6. What is a A substance made up from repeating monomers polymer? 7. What do What they are made from and the conditions (temperatures, etc.) in which they were made. the properties of polymers depend on? 8. What is They are produced using different catalysts and reaction conditions. the difference between how low density (LD) and high density (HD) poly(ethane) are made? 9. What are Polymers which consist of individual, tangled polymer chains. This means they do not have strong intermolecular forces between the chains. thermosofte ning polymers? 10. What Polymers which consist of polymer chains with cross links. This means that they have string forces between chains so do not melt. are thermosetti ng polymers? Question Date: Date: Date: Date: Date: Date: Date:

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C2.2 How structure influences properties_3

Key Recall Answer Question 1. How big 1-100nm (a few hundred atoms) are nanoparticle s? 2. What is They have different properties and have a high surface area to volume ratio. the difference between nanoparticle s and substances made of the same elements but larger? 3. What New computers, new catalysts, new coatings, highly selective sensors, stronger and lighter construction materials and new cosmetics such as sun tan creams and deodorants. sorts of new technologies could nanoparticle s be used to develop? Question Date: Date: Date: Date: Date: Date: Date:

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C2.3 Atomic structure, analysis and quantitative chemistry_1

Key Recall Question Answer 4. What are the names of the three parts of an atom? Proton, neutron and electron 5. What can the ‘mass number’ of an element tell us? The number of protons and neutrons 6. What can the ‘atomic number’ of an element tell The number of protons us? 7. What is the relative mass and charge of a proton? 1 and +1 8. What is the relative mass and charge of a neutron? 1 and 0 9. What is the relative mass and charge of an 0 and -1 electron? 10. What is an isotope? Atoms of the same element which have different numbers of neutrons (e.g. Hydrogen always has 1 proton but can have 1, 2 or 3 neutrons)

C2.3 Atomic structure, analysis and quantitative chemistry_2

Key Recall Answer Question 1. Which Carbon 12 (6 protons and 6 neutrons), 12 is the average value for the isotopes of carbon. isotope is the relative atomic mass of an atom compared to? 2. What is It is the sum of the relative atomic masses of the atoms shown in the formula. the relative formula mass of a compound? 3. What is 1 mole of the substance (which contains 6.02 x 1023 atoms) the relative formula mass of a substance when given in grams?

4. How do Add all the relative atomic masses of all the atoms together; CO2; Carbon = 12 plus Oxygen = 16 plus another Oxygen = 16 (because it is CO you the relative formula mass is 12 + 16 + 16 = 44 calculate the relative formula mass of carbon dioxide? (C = 12 and O = 16) 5. Which Instrumental methods because they are accurate, rapid and sensitive (think ARS) so can be used to identify elements and compounds in very small samples. methods are used to detect elements and compounds and why? 6. How is It can be used to identify additives in food. chemical analysis particularly useful in the food industry? 7. Which Paper chromatography. technique is used to identify artificial colours? 8. Which An instrumental method type of method is Gas chromatogra phy linked to mass spectroscop y (GC-MS) an example of? 9. What Separate a mixture of compounds. does GC-MS allow scientists to do? Question Date: Date: Date: Date: Date: Date: Date:

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C2.3 Atomic structure, analysis and quantitative chemistry_3

Key Recall Answer Question 1. How is Using a gas the substance to be analysed in GC-MS carried through the equipment? 2. What is The gas chromatography column packed with a solid material. the substance to be analysed passed through? 3. What Each element or compound within the substance travels through the column at different speeds, so the time taken can be used to help identify the compound. happens to the substance as it passes through the column? 4. What is A mass spectrometer the gas chromatogra phy column linked to? 5. What It will give different peaks which show how long each substance was in the column for (retention time). It will also give the relative molecular mass of each of the compounds separated. does the mass spectromete r show? 6. What is The molecular ion peak the name of the peak which shows the molecular mass? 7. If you The relative mass of the element and the relative formula mass of the compound want to calculate the percentage of a given element in a compound, which two pieces of information do you need? 8. What is The simplest ratio of elements in a compound the empirical formula? 9. What The masses or percentages of elements in a compound. information do you need to calculate the empirical formula? 10. Why is it 1. the reaction may not go to completion because it is reversible. not always 2. some of the product is lost when separated from the reaction mixture. possible to 3. Some of the reactants may react in ways different from the expected reaction obtain the calculated amount of a product when carrying out an experiment? Question Date: Date: Date: Date: Date: Date: Date:

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C2.3 Atomic structure, analysis and quantitative chemistry_4

Key Recall Answer Question 1. What is Yield another name for the ‘amount’ of product obtained in a chemical reaction? 2. What is The amount of product obtained compared with the maximum theoretical amount as a percentage (amount of product obtained/theoretical amount x 100) ‘percentage yield’? 3. What is a When the products of a reaction can react together to produce the original reactants. reversible reaction? 4. Give an Ammonium chloride ammonia + hydrogen chloride. example of a Hydrated copper sulphate (blue) anhydrous copper sulphate (white) + water reaction which is reversible Question Date: Date: Date: Date: Date: Date: Date:

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C2.4 Rates of reaction 1 Key Recall Question Answer 5. Which two ways can you measure rates of 1. Measuring the amount of reaction used in a reaction? given amount of time (amount of reactant used/time) 2. Measuring the amount of product formed in a given amount of time (amount of product formed/time) 6. Under what circumstances do chemical reactions When reacting particles collide with each other occur? with sufficient energy. 7. What is the ‘activation energy’ of a reaction? The minimum amount of energy particles must have to react. 8. What are the 5 ways to alter the rate of a reaction Temperature, concentration of reactants in a solution, gas pressure, surface area of solid reactants and presence of catalysts

C2.4 Rates of reaction_2

Key Recall Answer Question 1. Why does Because it increases the speed of the reacting particles (they have more energy) so they collide more frequently and more energetically. increasing temperature increase the rate of reaction? 2. Why does Because it increases the frequency of collisions (particles are closer together) increasing pressure of reacting gases increase the rate of reaction? 3. Why does Because it increases the frequency of collisions (more particles so more likely to collide). increasing the concentratio n of reactants in solutions increase the rate of reaction? 4. Why does Because it increases the frequency of collisions (more particles on the surface available for reactions) increasing the surface area of solid reactants increase the rate of reaction? 5. How You could grind it into a powder (if you added up the surface area of each tiny part of the powder this would be greater than surface area the original chip) could you increase the surface area of a marble (calcium carbonate) chip? 6. What is a It is a substance which changes the rate of chemical reactions without being used up. Each catalyst is specific to each reaction. catalyst? 7. Why are They increase the rate of reaction and therefore can reduce costs. catalysts important in industry? 8. Can you Platinum (in the ignition of hydrogen or the oxidation of ammonia). Manganese(IV) oxide or enzymes in yeast/potato (in the decomposition of hydrogen peroxide), etc. give some examples of catalysts? Question Date: Date: Date: Date: Date: Date: Date:

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C2.5 Exothermic and endothermic reactions

Key Recall Answer Question 1. What is A reaction which transfers energy to the surroundings (energy EXits) an exothermic reaction? 2. Can you Combustion reactions, many oxidation reactions and neutralisation. give three examples of exothermic reactions? 3. Can you Self-heating cans (e.g. coffee) and hand warmers. name some examples of everyday uses of exothermic reactions? 4. What is A reaction which takes in energy from the surroundings (heat ENters) an endothermic reaction? 5. Can you Thermal decompositions give an example of an endothermic reaction? 6. Can you Sports injury packs. name some examples of everyday uses of endothermic reactions? 7. If a Endothermic reversible reaction is exothermic in one direction will it be exothermic or endothermic in the other direction? 8. Can you Hydrated copper sulphate (blue) anhydrous copper sulphate (white) + water name an This is endothermic in this direction but the reverse reaction is exothermic. example of a reversible reaction which is endothermic and exothermic? 9. What Dissolves in a solvent (typically water) does soluble mean? 10. What Does not dissolve in a solvent (typically water) does insoluble mean? Question Date: Date: Date: Date: Date: Date: Date:

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C2.6 Acids, bases and salts_1

Key Recall Answer Question 1. What are (s) solid, (l) liquid, (aq) aqueous and (g) gas. the four state symbols used in chemical reactions? 2. What Dissolved in water (a solution) does aqueous mean? 3. What Metals, insoluble bases, alkalis three substances can be used to react with acids in order to make a soluble salt? 4. What is Bases are insoluble metal hydroxides or oxides and alkalis are soluble hydroxides. the difference between a base and an alkali? 5. Why can Some are too reactive (e.g. sodium) and some are not reactive enough (e.g. gold) you not use all metals when reacting them with acid to make a soluble salt? 6. How do Add the base to the acid until no more will react then filter the excess (unreacted) solid off. you make an insoluble salt using an acid and a base? 7. What is An indicator used when an acid reacts with an alkali to make a soluble salt in order to detect when the reaction has happened to completion? 8. How can Crystallise the solutions (allow the water to evaporate leaving behind the salt) you get a solid salt from a salt solution? 9. Can you React sodium hydroxide (alkali) with hydrochloric acid (acid) to completion. Use universal indicator to detect a neutral solution which will be green colour. Add charcoal to remove the indicator suggest how then filter this away. Crystallise the salt using an evaporating dish and gentle heat. to make sodium chloride? Question Date: Date: Date: Date: Date: Date: Date:

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C2.6 Acids, bases and salts_2

Key Recall Answer Question 1. How do Mix appropriate amounts of solutions of ions so that a precipitate is formed. you make an insoluble salt? 2. How can To remove unwanted ions from solutions, e.g. in treating water or effluent. precipitation be used in industry? 3. What are Metal oxides and hydroxides which are insoluble. bases? 4. What are Hydroxides which are soluble. alkalis? 5. In a The metal in the base or alkali and the type of acid used. reaction between an acid and a base or alkali, what does the name of the alt produced depend on? 6. Which Chlorides. type of soluble salt does hydrochloric acid produce when reacted with a base or alkali? 7. Which Nitrates. type of soluble salt does nitric acid produce when reacted with a base or alkali? 8. Which Sulphates. type of soluble salt does sulphuric acid produce when reacted with a base or alkali? 9. If Potassium sulphate. sulphuric acid reacts with potassium hydroxide what is the name of the soluble salt produced? 10. If zinc Zinc nitrate oxide reacts with nitric acid what is the name of the soluble salt produced? Question Date: Date: Date: Date: Date: Date: Date:

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C2.6 Acids, bases and salts_3

Key Recall Answer Question 1. When Alkaline ammonia dissolves in water does it produce an acid or alkaline solution? 2. How is It is used to produce ammonium salts which are useful as fertilisers ammonia solution useful? 3. Which H+ ion makes solutions acidic? 4. Which OH- ion makes solutions alkaline? 5. What How acidic or alkaline a solution is (essentially how many H+ or OH- ions are in the solution) does the pH scale measure? 6. What is 0-14 the range of the pH scale? 7. What is a 7 neutral pH? 8. What is 1 or 2 the pH of a strong acid? 9. What is 13 or 14 the pH of a strong alkali? 10. What is When and acid and alkali react so the H+ ions react with the OH- ions to produce water. a H+(aq) + OH- (aq)  H2O(l) neutralisatio n reaction? Question Date: Date: Date: Date: Date: Date: Date:

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C2.7 Electrolysis

Key Recall Answer Question 1. Why Because when solid the ions are strongly attracted to each other so cannot move. Dissolving or melting the ionic substance means the ions are free to move within the liquid or solution. must an ionic substance be melted or dissolved in water before electrolysis can be carried out? 2. In order Melted to carry out electrolysis on lead bromide does it need to be dissolved or melted? 3. What It gets broken down into its elements (lead and bromine) happens when you pass an electric current through molten lead bromide? 4. What is Electrolyte. the term used for a substance that is broken down by electrolysis? 5. What Positively charged ions move to the negative electrode and negatively charged ions move to the positive electrode. happens to the positive and negative ions during electrolysis? 6. What The positive ions gain electrons (reduction) happens to the positive ions at the negative electrode? 7. What The negative ions lose electrons (oxidation) happens to the negative ions at the positive electrode? 8. Does No, it is about the loss or gain of electrons. Oxidation Is the Loss of electrons and Reduction Is the Gain. (OILRIG) oxidation- reduction reactions always involved oxygen? 9. If there is The reactivity of the elements involved. The least reactive will be most likely to gain or lose electrons at the electrodes. a mixture of ions in the electrolyte, what will the products formed depend on?

10. How are By half equations e.g. 2Cl-  Cl2 + 2e- reactions at or 2Cl- - 2e-  Cl2 (where e- represents an electron) electrodes represented ? Question Date: Date: Date: Date: Date: Date: Date:

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C2.7 Electrolysis_2

Key Recall Answer Question 1. What is Where electrolysis is used to plate objects for a variety of reasons e.g. copper plating or silver plating (cutlery, etc.) electroplatin g? 2. How is Using a molten (melted) mixture of aluminium oxide and a substance called cryolite. electrolysis used to manufacture aluminium? 3. Why is It lowers the melting point of aluminium oxide. cryolite required in the electrolysis to produce aluminium? 4. In the Aluminium electrolysis of aluminium oxide, what is formed at the negative electrode? 5. In the Oxygen electrolysis of aluminium oxide, what is formed at the positive electrode? 6. Which Carbon element are electrodes typically made from? 7. If oxygen The oxygen reacts with the carbon in the electrode to form carbon dioxide and the electrode will need to be regularly replaced. is formed at an electrode, what usually happens? 8. What are Hydrogen and chlorine (at electrodes). Sodium hydroxide solution is also produced. the products of the electrolysis of sodium chloride solution? 9. How are Sodium hydroxide is important for the production of soap and chlorine for the production of bleach and plastics. the products of the electrolysis of sodium chloride solution use in industry? - - 10. Can you 2Cl - 2e à Cl2 write the half equation for the oxidation reaction at the positive electrode in the electrolysis of sodium chloride solution? + - 11. Can you 2H + 2e à H2 write the half equation for the reduction reaction at the negative electrode in the electrolysis of sodium chloride solution? Question Date: Date: Date: Date: Date: Date: Date:

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