9701_w19_qp_22 - revisedeck

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In the Periodic Table, the p block contains elements whose outer electrons are found in the psubshell. Elements in the pblock show a general increase in first ionisation energy as the atomic number increases. Draw the shape of a p orbital. Write an equation to show the first ionisation energy of silicon. Explain why there is a general increase in first ionisation energies of the elements across Period3. ElementA is in the pblock. The graph shows the successive ionisation energies for the removal of the first ten electrons of A. number of electrons removed ionisation energy State and explain the group of the Periodic Table that element A belongs to. group number explanation Silicon is found in many compounds in the Earth’s crust. Silicon has only three naturally occurring isotopes, 28Si, 29Si and 30Si. The table shows data for 28Si, 29Si and 30Si. 28Si 29Si 30Si relative isotopic mass 28.0 29.0 30.0 A sample of silicon contains 92.2% 28Si. The total percentage abundance of 29Si and 30Si in the sample is 7.8%. The relative atomic mass, Ar, of silicon in the sample is 28.09. Calculate the percentage abundance of 30Si. Give your answer to one decimal place. percentage abundance of 30Si = % Silicon reacts with nitrogen gas to form Si3N4. Si3N4 is a solid with a melting point of 1900 °C. It is insoluble in water and does not conduct electricity when molten. Suggest the type of bonding in and structure of Si3N4. Explain your answer. Sulfur-containing compounds, such as C2H5SH, are found in fossil fuels, and produce SO2 when they are burned. Write the equation to show the complete combustion of C2H5SH. State why the presence of SO2 in the atmosphere has environmental consequences. Describe one of the consequences on the environment. SO2 can react with ozone, O3, to form SO3 in two different reactions. In one reaction, SO2 reacts with O3 until a dynamic equilibrium is established. SO2+ O3SO3+ O2State and explain the effect of an increase in pressure on the composition of the equilibrium mixture. In the other reaction, a different equilibrium is established at 300 K as shown. 3SO2+ O33SO3ΔH = +462.3 kJ mol–1 Suggest a temperature needed to increase the yield of SO3 at equilibrium. Explain your answer.

1. Atomic structure → 1.4. Ionisation energy

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Oxygen is the most abundant element in the Earth’s crust. It reacts with other elements to form stable compounds, ions and molecules. Complete the table to give the formulae and acid/base behaviour of some of the oxides of the Period3 elements. element sodium aluminium silicon phosphorus sulfur formula of oxide Na2O SO3 acid/base behaviour amphoteric Group2 elements form stable hydroxides, with general formula M(OH)2, where M is the Group2 element. Beryllium hydroxide, Be(OH)2, is an amphoteric compound that shows similar chemical reactions to aluminium oxide. State the meaning of the term amphoteric. Write an ionic equation for the reaction of magnesium hydroxide, Mg(OH)2, with hydrochloricacid. Two methods of preparing strontium hydroxide are shown. strontium strontium hydroxide strontium oxide H2O reaction 1 H2O reaction 2 State one difference between the observations you would make for reaction 1 and reaction2. State how the solubility of the Group2 hydroxides changes down the group. Sodium peroxide, Na2O2, reacts with CO2. Na2O2+ CO2Na2CO3+ 2O2The partial pressure of CO2in a 0.500 dm3 sample of air is 5.37 kPa at 20 °C. Calculate the amount, in moles, of CO2present in the sample of air at 20 °C. amount of CO2= mol Calculate the mass of Na2O2that would react fully with the amount of CO2calculated in . mass of Na2O2= g The peroxide ion, O2 2–, has a single covalent bond between the two oxygen atoms. Each oxygen atom carries a negative charge. Draw a ‘dot-and-cross’ diagram for the peroxide ion. Show outer electrons only.

9. The Periodic Table: chemical periodicity → 9.2. Periodicity of chemical properties of the elements in Period 3

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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A series of reactions for phosphorus and its compounds is shown. P PCl 5 excess Cl 2 reaction 1 H2O reaction 2 H3PO4 (NH4 +)(H2PO4 –) NH3 reaction 3 State what you would observe in reaction1. State the type of reaction that occurs in reaction2. H3PO4 can be produced by direct reaction of phosphorus with nitric acid. P + 5HNO3 H2O + 5NO2 + H3PO4 Use oxidation numbers to show that this reaction is a redox reaction. Reaction3 is a neutralisation reaction in which NH3 acts as a base. Explain how NH3 acts as a base in reaction3. Draw the three-dimensional shape of the ammonium ion, NH4 +. Give the bond angle. bond angle = ° State the industrial importance of compounds such as (NH4 +)(H2PO4 –). PCl 5 can be used to convert alcohols to halogenoalkanes. Write an equation for the reaction of C2H5OH with PCl 5 to form C2H5Cl. State the type of reaction in . Halogenoalkanes can also be prepared by reacting alcohols with hydrogen halides, such as HCl and HI. ● HCl is prepared using NaCl and concentrated H2SO4. ● HI is prepared by reacting NaI with concentrated H3PO4. Suggest why HI is not prepared by the reaction of NaI with concentrated H2SO4. The rate of the hydrolysis reaction of halogenoalkanes with NaOHis dependent on the halogen that is bonded to carbon. State and explain the order of reactivity when NaOHreacts separately with C2H5Cl, C2H5Br and C2H5I.

15. Halogen compounds → 15.1. Halogenoalkanes

14. Hydrocarbons → 14.2. Alkenes

12. Nitrogen and sulfur → 12.1. Nitrogen and sulfur

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Prenol is a naturally occurring organic molecule found in many fruits. It contains both an alkene and an alcohol functional group. C C prenol H CH2OH H3C H3C Prenol can be formed by the reaction of G with NaOH. Complete the diagram to show the mechanism of the reaction between G and NaOHto form prenol. Include all relevant charges, partial charges, lone pairs and curly arrows. C C prenol H CH2OH H3C H3C C C G H C Cl H H H3C H3C Prenol reacts with steam to form a mixture of three isomers, J, K and L, of molecular formula C5H12O2. When J is heated with excess acidified potassium dichromate(it forms an organic product which shows no reaction with 2,4‑DNPH. Draw the structure of J. K and L are stereoisomers with molecular formula C5H12O2. K and L both react when heated with excess acidified potassium dichromate(to form M, C5H8O3. M forms an orange precipitate on reaction with 2,4‑DNPH. Give the structural formula of K and L. Name the type of stereoisomerism shown by K and L. Give the balanced equation to represent the reaction of K, C5H12O2, with acidified potassium dichromate(to form M, C5H8O3. Use [O] to represent an atom of oxygen provided by the oxidising agent. Prenol contains an alkene functional group. Describe a chemical test to confirm the presence of an alkene functional group. Give the result of the test. Prenol can be polymerised to form poly. Draw one repeat unit of poly. Isoprenol is a structural isomer of prenol. C C isoprenol CH3 CH2CH2OH H H The series of reactions shows how isoprenol can be used to form Q, a sweet-smelling liquid. isoprenol H2 and Ni reaction 1 acidified potassium dichromate(heat under reflux C2H5OH and H2SO4 heat under reflux N P O OH OH Q Give the name of N. Isoprenol is a liquid. Ni acts as a catalyst for reaction1. Identify the type of catalysis shown by Ni in reaction1. Draw the skeletal formula of Q and suggest one commercial use of Q. Q commercial use P can be produced as shown. HCl H+ / H2O reaction I reaction II Cl reaction III C N O P OH The progress of reactionI can be monitored using infra-red spectroscopy. One absorption that can be used to monitor the progress of this reaction is that of C–Cl at 730 cm–1. Identify another absorption that can be used to monitor the progress of this reaction. In your answer, you should refer to the specific bond and its corresponding absorption range in wavenumbers. State the reagentneeded for reactionII. Name the type of reaction that occurs in reactionIII. The yield of reactionI is very low. Explain why.

16. Hydroxy compounds → 16.1. Alcohols

14. Hydrocarbons → 14.2. Alkenes

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