9701_m16_qp_22
A paper of Chemistry, 9701
Questions:
5
Year:
2016
Paper:
2
Variant:
2
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1
This question is about Period 3 elements and their compounds. Give an explanation for each of the following statements. The atomic radius decreases across Period 3 (Na to Ar). The first ionisation energy of sulfur is lower than that of phosphorus. Sodium is a better electrical conductor than phosphorus. Magnesium is a better electrical conductor than sodium. The flow chart below shows a series of reactions. Awhite precipitate, EB+ CD+ MgHNO3reagent Xheat MgO+ H2O+ Give the formula of each of the compounds A to D. A B C D E reacts with dilute aqueous acid to produce a gas that turns limewater cloudy. Suggest the identity of reagent X.
9. The Periodic Table: chemical periodicity  →  9.2. Periodicity of chemical properties of the elements in Period 3
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2
Spathose is an iron ore that contains iron(carbonate, FeCO3. The percentage of iron(carbonate in spathose can be determined by titration with acidified potassium dichromate(solution using a suitable indicator. The ionic equation is shown below. Cr2O7 2–+ 14H++ 6Fe2+→ 2Cr3++ 6Fe3++ 7H2OA 5.00 g sample of spathose was reacted with excess concentrated hydrochloric acid and then filtered. The filtrate was made up to 250 cm3 in a volumetric flask with distilled water. A 25.0 cm3 sample of the standard solution required 27.30 cm3 of 0.0200 mol dm–3 dichromate(solution for complete reaction. Calculate the amount, in moles, of dichromate(ions used in the titration. amount = mol Use your answer to to calculate the amount, in moles, of Fe2+ present in the 25.0 cm3 sample. amount = mol Use your answer to to calculate the amount, in moles, of Fe2+ present in the 250 cm3 volumetric flask. amount = mol Use your answer to to calculate the mass of iron(carbonate present in the sample of spathose. mass = g Calculate the percentage of iron(carbonate in the sample of spathose. percentage of iron(carbonate = % Iron ores containing iron(compounds can be analysed using a similar method. A standard solution of an aqueous iron(compound is reacted with aqueous tin(chloride. Aqueous tin(chloride and aqueous iron(chloride are the products of this reaction. Write an ionic equation for this reaction. Do not include state symbols. Any excess tin(chloride can be removed by reaction with HgCl 2. A white precipitate of Hg2Cl 2 is produced. Complete the equation for this reaction. ( ) + HgCl 2→ SnCl 4( ) + Hg2Cl 2( )
11. Group 17  →  11.4. The reactions of chlorine
10. Group 2  →  10.1. Similarities and trends in the properties of the Group 2 metals, magnesium to barium, and their compounds
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3
Over one million tonnes of hydrogen cyanide, HCN, are produced each year using the Andrussow process. The overall equation for the reaction is shown. CH4+ NH3+ 1 2 1 O2HCN+ 3H2ODraw a dot-and-cross diagram to represent the bonding in a molecule of ammonia, NH3, and state the shape of the molecule. shape of molecule A molecule of hydrogen cyanide, HCN, is shown. N C H The bonding between the carbon and nitrogen atoms consists of one sigma (σ) bond and two pi (π) bonds. Sketch the shape of the sigma bond and one of the pi bonds in the space below. Show clearly the position of the atomic nuclei in each diagram. sigma (σ) pi (π) The reaction exists as a dynamic equilibrium. Explain what is meant by the term dynamic equilibrium. State and explain how the amounts of the chemicals present in the equilibrium mixture will change when the pressure is increased. The process uses a platinum catalyst, which increases the rate of reaction. Sketch a Boltzmann distribution on the axes given below and use your diagram to explain how the platinum catalyst increases the rate of the reaction. number of molecules molecular energy The reaction of hydrogen cyanide with propanone is an important first step in many organic syntheses. Give the full name of the mechanism of this reaction. Complete the diagram to show the mechanism of the reaction of hydrogen cyanide with propanone. Draw the structure of the intermediate and the product of the reaction. Include all relevant charges, partial charges, curly arrows and lone pairs. O C –CN CH3 H3C
17. Carbonyl compounds  →  17.1. Aldehydes and ketones
14. Hydrocarbons  →  14.2. Alkenes
14. Hydrocarbons  →  14.1. Alkanes
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The following compounds were all found to be components of a sample of petrol. CH3(CH2)2CH3 (CH3)3CCH2CH(CH3)2 H C H H J G H3C CH3 H3C C OH Give the molecular formula of compound G. Give the empirical formula of compound H. Draw the skeletal formula of compound J. Write an equation to represent the complete combustion of compound H. Fossil fuels are often contaminated with sulfur. State and explain why supplies of fossil fuels that contain sulfur pose a problem to the environment. The boiling points of compounds G, H and J are shown below. compound G H J boiling point / °C Explain the differences in the boiling points of the three compounds. Compound J can be produced from 2-chloro-3-methylbutane, C5H11Cl. Give the reagentand conditions for this reaction.
13. An introduction to AS Level organic chemistry  →  13.1. Formulas, functional groups and the naming of organic compounds
14. Hydrocarbons  →  14.1. Alkanes
11. Group 17  →  11.2. The chemical properties of the halogen elements and the hydrogen halides
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Some reactions of compound P, C5H8O, are shown. H2Nicatalyst OH–I2compound Q compound R compound S compound P compound T + O O –O cold, acidified KMnO4NaBH4 Give the structures for organic compounds Q, R, S and T. Q T R S Give the systematic name of compound P. What would you observe when compound P is reacted with 2,4-dinitrophenylhydrazine (2,4-DNPH)? Compound U contains a chiral centre and has the same molecular formula as compound P, C5H8O. • Compound U readily decolourises a sample of bromine water. • Compound U does not show cis-trans isomerism. • When compound U is heated under reflux in the presence of excess acidified potassiumdichromate(, the organic product gives the infra-red spectrum shown. infra-red spectrum of product wavenumber / cm–1 transmittance / % Use the information given to suggest a structure for compound U. Explain your answer.
13. An introduction to AS Level organic chemistry  →  13.1. Formulas, functional groups and the naming of organic compounds
17. Carbonyl compounds  →  17.1. Aldehydes and ketones
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