9701_w13_qp_23
A paper of Chemistry, 9701
Questions:
5
Year:
2013
Paper:
2
Variant:
3
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1
Ammonia, NH3, and methane, CH4, are the hydrides of elements which are next to one another in the Periodic Table. In the boxes below, draw the ‘dot-and-cross’ diagram of a molecule of each of these compounds. Show outer electrons only. State the shape of each molecule. NH3 CH4 shape shape Ammonia is polar whereas methane is non-polar. The physical properties of the two compounds are different. Explain, using ammonia as the example, the meaning of the term bond polarity. Explain why the ammonia molecule is polar. State one physical property of ammonia which is caused by its polarity. For Examiner’s Use When ammonia gas is mixed with hydrogen chloride, white, solid ammonium chloride is formed. State each type of bond that is present in one formula unit of ammonium chloride and how many of each type are present. You may draw diagrams.
11. Group 17  →  11.2. The chemical properties of the halogen elements and the hydrogen halides
3. Chemical bonding  →  3.6. Intermolecular forces, electronegativity and bond properties
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2
For Examiner’s Use Petrol and diesel fuel are both used in internal combustion engines. Petrol may be regarded as having the formula C9H20 and diesel fuel as having the formula C14H30. To which class of compounds do these two hydrocarbons belong? Write a balanced equation for the complete combustion of petrol. When petrol or diesel fuel are used in internal combustion engines, several different products of the incomplete combustion of the fuel may be formed. Name two of these products that do not contain hydrogen. and Choose one of these and state a hazard it causes. product hazard Write a balanced equation for the formation of one of the products in from diesel fuel. For Examiner’s Use Defi ne the term standard enthalpy change of combustion. A 1.00 cm3 sample of C14H30 was completely burnt in air. The heat produced raised the temperature of 250 g of water by 34.6 °C. Assume no heat losses occurred during this experiment. The density of C14H30 is 0.763 g cm–3. Use relevant data from the Data Booklet to calculate the amount of heat released in this experiment. Use the data above and your answer to to calculate the energy produced by the combustion of 1 mol of C14H30.
14. Hydrocarbons  →  14.1. Alkanes
5. Chemical energetics  →  5.1. Enthalpy change, \(\Delta H\)
2. Atoms, molecules and stoichiometry  →  2.4. Reacting masses and volumes (of solutions and gases)
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3
For Examiner’s Use The elements of Group VII of the Periodic Table show variation in their properties. Complete the table below, stating the colour of each element in its normal state at room temperature. halogen melting point / °C colour chlorine –101 bromine –7 iodine Briefl y explain why the melting points of the halogens increase from chlorine to iodine. The halogens form many interhalogen compounds in which two different halogens are combined. One such compound is bromine monochloride, BrCl. Complete the electronic confi gurations of chlorine and bromine. chlorine 1s22s22p6 bromine 1s22s22p6 Draw a 'dot-and-cross' diagram of the BrCl molecule. Show outermost electrons only. For Examiner’s Use Interhalogen compounds like BrCl have similar properties to the halogens. By considering your answers to and , predict the physical state of BrCl at room temperature. Explain your answer. physical state explanation Suggest the colour of BrCl. Cl 2 and BrCl each react with aqueous KI. Describe what would be seen when Cl 2 is bubbled through aqueous KI for several minutes. initially after several minutes Construct an equation for the reaction that occurs. Suggest an equation for the reaction that occurs between BrCl and aqueous KI. How do Cl 2 and BrCl behave in these reactions?
11. Group 17  →  11.1. Physical properties of the Group 17 elements
11. Group 17  →  11.2. The chemical properties of the halogen elements and the hydrogen halides
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4
For Examiner’s Use Compound Q is a viscous liquid which is very soluble in water. The Mr of Q is 90.0. Three possible structures for Q are shown below. R S T HOCH2CH2CO2H HOCH2CO2CH3 HCO2CH2CH2OH What type of isomerism do R, S and T show? What oxygen-containing functional groups are present in R, S and T? Give their full names. R and S and T and Which functional groupin will react with sodium carbonate? Which functional groupin will react with sodium metal? When 0.002 mol of Q is reacted with an excess of solid sodium carbonate, Na2CO3, 24 cm3 of carbon dioxide, measured at room temperature and pressure, is produced. Calculate the amount, in moles, of carbon dioxide produced in this reaction. Hence calculate the amount, in moles, of carbon dioxide produced by 1 mol of Q. For Examiner’s Use When 0.002 mol of Q is reacted with an excess of metallic sodium, 48 cm3 of hydrogen, measured at room temperature and pressure, is produced. Calculate the amount, in moles, of hydrogen molecules produced in this reaction. Hence calculate the amount, in moles, of hydrogen molecules produced by 1 mol of Q. Use your answers to and to deduce which structure, R, S or T, corresponds to the structure of Q and write balanced equations for the reactions that occurred. identity of Q is equation for reaction with sodium carbonate equation for reaction with sodium metal
11. Group 17  →  11.4. The reactions of chlorine
2. Atoms, molecules and stoichiometry  →  2.4. Reacting masses and volumes (of solutions and gases)
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5
For Examiner’s Use The molecular formula C4H9OH represents four different alcohols, W, X, Y and Z. W X Y Z CH3CH2CH2CH2OH CH3CH2CH(OH)CH3 (CH3)2CHCH2OH (CH3)3COH Draw the skeletal formula of Z. Acidifi ed potassium dichromate(is used as an oxidising agent in organic chemistry. Give the structural formula of the organic product formed when each of the four alcohols above is heated under refl ux with acidifi ed potassium dichromate(. If you believe that no reaction occurs, write 'no reaction' in the box. W X Y Z For Examiner’s Use One of the alcohols, W, X, Y or Z, can be dehydrated to give more than one organic product. Identify this alcohol and give the structural formulae of two of the products. alcohol product 1 product 2
16. Hydroxy compounds  →  16.1. Alcohols
13. An introduction to AS Level organic chemistry  →  13.1. Formulas, functional groups and the naming of organic compounds
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