0620_s19_qp_41 - revisedeck

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This question is about the structures of atoms and ions. Define the term proton number. Complete the table to show the number of protons, neutrons and electrons present in atoms of 24Mg and 26Mg . number of protons number of neutrons number of electrons 24Mg 26Mg What term is used to describe atoms of the same element, such as 24Mg and 26Mg ? Explain why the chemical properties of 24Mg and 26Mg are the same. Complete the table to identify the atoms and ions which have the following numbers of protons, neutrons and electrons. number of protons number of neutrons number of electrons 23Na+ State the electronic structure of the following atom and ion. Al S2–

2. Atoms, elements and compounds → 2.2. Atomic structure and the Periodic Table

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Z is a covalent substance. In an experiment, a sample of pure solid Z was continually heated for 11minutes. The graph shows how the temperature of the sample of pure Z changed during the first 9minutes. time / minutes temperature / °C What is the melting point of pure Z? °C The sample of pure Z began to boil at 9minutes. It was boiled for 2minutes. Use this information to sketch on the grid how the temperature of the sample of pure Z changed between 9minutes and 11minutes. The sample of pure Z was continually heated between 2minutes and 5 minutes. Explain, in terms of attractive forces, why there was no increase in the temperature of the sample of pure Z between 2minutes and 5minutes. Describe how the motion of particles of pure Z changed from 0minutes to 2minutes. The experiment was repeated using a solid sample of impure Z. Suggest the differences, if any, in the melting point and boiling point of the sample of impureZ compared to the sample of pureZ. melting point boiling point A sample of pure Z was allowed to cool from 120 °C to 20 °C. The total time taken was 8minutes. Starting from point ×, sketch on the grid how the temperature of the sample of pureZ changed between 0minutes and 8minutes. time / minutes temperature / °C

1. States of matter → 1.1. Solids, liquids and gases

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Zinc and copper are elements next to each other in the Periodic Table. Zinc is obtained from zinc blende in a two-step process. ● ● In step1, zinc blende is converted into zinc oxide. ● ● In step2, zinc oxide is converted into zinc in a blast furnace. Outline how each of these steps are done. In your answer: ● ● give one chemical equation for each step ● ● describe how zinc is removed from the blast furnace in step2. step 1 chemical equation step 2 chemical equation removal of zinc in step 2 Name the alloy formed when zinc is mixed with copper. Copper is a transition element. It can have variable oxidation states. State two other chemical properties of transition elements which make them different from GroupI elements. A compound of copper can be used to test for water. State the full name of this compound of copper. State the colour change that occurs when water is added to this compound of copper. from to Aqueous potassium iodide reacts with aqueous copper(sulfate to produce iodine. Balance the chemical equation for this reaction. KI + CuSO4 CuI + I2 + K2SO4 Deduce the charge on the copper ion in CuI. In terms of electron transfer, explain why copper is reduced in this reaction. Identify the reducing agent.

9. Metals → 9.4. Reactivity series

4. Electrochemistry → 4.1. Electrolysis

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Ethanoic acid is a weak acid and hydrochloric acid is a strong acid. Both ethanoic acid and hydrochloric acid dissociate in aqueous solution. Define the term acid. The chemical equation shows the changes which occur when the strong acid, hydrochloricacid, is added to water. HCl H++ Cl –Complete the chemical equation to show the changes which occur when the weak acid, ethanoicacid, is added to water. CH3COOHA student does experiments to show that hydrochloricacid is a strong acid and ethanoicacid is a weak acid. The student adds an excess of hydrochloricacid and an excess of ethanoicacid to separate samples of lumps of calciumcarbonate. Only the identity of the acid is changed between the experiments. All other conditions are kept the same. State two observations which would show that hydrochloricacid is a stronger acid than ethanoicacid. The student uses the same size container and checks that the pressure is the same for each experiment. State three other conditions which must be kept the same to ensure fair testing. Hydrochloric acid produces salts called chlorides. Magnesium carbonate reacts with hydrochloric acid to produce magnesiumchloride. MgCO3 + 2HCl MgCl 2 + H2O + CO2 A student used 50.00 cm3 of 2.00 mol / dm3 hydrochloric acid in an experiment to produce magnesiumchloride. Calculate the mass, in g, of magnesium carbonate needed to react exactly with 50.00 cm3 of 2.00 mol / dm3 hydrochloric acid using the following steps. ● ● Calculate the number of moles of HCl present in 50.00 cm3 of 2.00 mol / dm3 HCl. mol ● ● Determine the number of moles of MgCO3 which would react with 50.00 cm3 of 2.00 mol / dm3HCl. mol ● ● Calculate the relative formula mass, Mr, of MgCO3. Mr of MgCO3 = ● ● Calculate the mass of MgCO3 needed to react exactly with 50.00 cm3 of 2.00 mol / dm3HCl. mass = g A student prepares crystals of magnesium chloride by adding an excess of magnesiumcarbonate to 50.00 cm3 of 2.00 mol / dm3 hydrochloricacid. The student filters the mixture and rinses the residue. Why does the student add an excess of magnesium carbonate? Why does the student rinse the residue? Describe how the student would obtain pure crystals of magnesium chloride from the filtrate. Silver chloride, AgCl, is insoluble. It can be made by a precipitation reaction between aqueous bariumchloride and a suitable aqueous silver salt. What is meant by the term precipitate? Name a suitable silver salt to use to prepare silverchloride. Complete the chemical equation to show the formation of insoluble silver chloride from aqueous barium chloride and the silver salt you have named. name of a suitable silver salt BaCl 2 + +

7. Acids, bases and salts → 7.1. The characteristic properties of acids and bases

12. Experimental techniques and chemical analysis → 12.5. Identification of ions and gases

11. Organic chemistry → 11.7. Carboxylic acids

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The structures of five alkenes, A, B, C, D and E, are shown. C C A H H H H C C B CH3 H H H C C C CH2CH3 H H H C C D CH2CH2CH3 H H H C C E CH2CH2CH2CH3 H H H What is the general formula of alkenes? What is the molecular formula of alkeneD? Predict which alkene, A, B, C, D or E, has the highest boiling point. Explain your answer. alkene explanation Which alkene, A, B, C, D or E, diffuses most quickly? Explain your answer. alkene explanation A student added aqueous bromine to alkeneC. C C C CH2CH3 H H H Describe the colour change seen and draw the structure of the product. Show all of the atoms and all of the bonds. colour change from to structure Two different alcohols can be produced from alkeneB by an addition reaction. C C B CH3 H H H Draw the structures of the two alcohols. Show all of the atoms and all of the bonds. State the reagent and conditions needed to produce an alcohol from alkeneB. reagent conditions AlkeneC can be converted into a polymer. C C C CH2CH3 H H H What type of polymerisation occurs? Suggest the name of the polymer formed. Complete the chemical equation to show this polymerisation. C C CH2CH3 H H H n State the empirical formula of the polymer formed.

11. Organic chemistry → 11.5. Alkenes

11. Organic chemistry → 11.8. Polymers

11. Organic chemistry → 11.1. Formulae, functional groups and terminology

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