9701_w22_qp_21
A paper of Chemistry, 9701
Questions:
5
Year:
2022
Paper:
2
Variant:
1
Login to start this paper & get access to powerful tools
1
Atoms with nuclei containing an odd number of protons tend to have fewer isotopes than those with an even number of protons. Gallium has two stable isotopes, 69Ga and 71Ga. Complete Table1.1 to show the numbers of protons, neutrons and electrons in the two stable isotopes of gallium. Table 1.1 isotope number of protons number of neutrons number of electrons 69Ga 71Ga  Define relative atomic mass. The relative atomic mass of gallium, Ar, is 69.723. The relative isotopic masses of 69Ga and 71Ga are: 69Ga, 68.926; 71Ga, 70.925. Use this information to calculate the percentage abundance of 69Ga in elemental gallium. Show your working. Assume that the element contains only the 69Ga and 71Ga isotopes. Give your answer to four significant figures.  percentage abundance of 69Ga = %  Potassium also has two stable isotopes. Both isotopes have the same chemical properties. Explain why both isotopes of potassium have the same chemical properties. State the full electronic configuration of an atom of potassium. The first, second and third ionisation energies of potassium are 418, 3070 and 4600 kJ mol–1, respectively. Use this information to explain why potassium is in Group1. 
1. Atomic structure  →  1.2. Isotopes
Open
2
Magnesium shows reactions typical of a Group2 metal. Draw a labelled diagram to show the bonding in magnesium metal.  Fig.2.1 shows some reactions of magnesium and its compounds. Mg MgCO3 MgO reaction 1 HCl reaction 3 Ca(OH)2reaction 2 HCl reaction 4 heat MgCl 2 Mg(OH)2 Identify the other products of reactions 1 and 2. reaction 1 reaction 2  Reaction3 is used to form a precipitate of Mg(OH)2 from MgCl 2. State why Ca(OH)2would not form a precipitate of Ba(OH)2 from BaCl 2. State the type of reaction that occurs in reaction4. 1 cm3 of MgCl 2is placed in a test-tube. A few drops of AgNO3are added, followed by 1 cm3 of dilute NH3. State in full what is observed in this experiment. When 1 cm3 of MgCl 2is added to 1 cm3 of Br2in a test-tube, the solution remains orange. Explain this observation. 
10. Group 2  →  10.1. Similarities and trends in the properties of the Group 2 metals, magnesium to barium, and their compounds
Open
3
Some of the common chlorides of Period3 elements are shown in the list. NaCl MgCl 2 Al Cl 3 SiCl 4 PCl 5 From this list, identify: all the chlorides that have giant ionic structures in the solid state all the chlorides that react vigorously with water to form strongly acidic solutions the chloride that dissolves in water to form a neutral solution the chloride formed from the element with the highest melting point. NaCl is one product of the reaction of chlorine gas and cold aqueous sodium hydroxide. Identify the other products. PCl 5 reacts with alcohols to form chloroalkanes. Identify this type of reaction. Draw the structure of the organic product formed in the reaction of an excess of PCl 5 with butane-1,3-diol.  Sulfur, S8, reacts with chlorine to form several different chlorides. The most common are S2Cl 2 and SCl 2. SCl 2 forms when sulfur reacts with an excess of chlorine. reaction1 S8+ 4Cl 2→ 4S2Cl 2∆Hr = –58.2 kJ mol–1 reaction2 S2Cl 2+ Cl 22SCl 2∆Hr = –40.6 kJ mol–1 SCl 2 is a cherry-red liquid that reacts vigorously with water to form an acidic solution. Use this information to deduce the bonding and structure shown by SCl 2. Explain your answer. Calculate the enthalpy change of formation, ∆Hf, of SCl 2. You may find it useful to use Hess’s Law to construct an energy cycle.  enthalpy change of formation of SCl 2, ∆Hf = kJ mol–1  State the effect of a decrease in pressure on the position of equilibrium in reaction2. Explain your answer. Fig.3.1 shows the two structural isomers of S2Cl 2. isomer I isomer II Cl Cl S S Cl Cl S S Define the term structural isomer. Suggest a value for the Cl –S–S bond angle in isomerI. Explain your answer. bond angle = ° explanation  Draw a dot-and-cross diagram to show the bonding in isomerII. Show outer shell electrons only.  
9. The Periodic Table: chemical periodicity  →  9.2. Periodicity of chemical properties of the elements in Period 3
Open
4
Organic compounds can be distinguished using chemical tests. Table4.1 shows four pairs of compounds. Table 4.1 organic compounds reagent positive result of chemical test on identified compound A1 O O OH OH OH HO O OH HO A2 O O O B1 B2 C1 C2 D1 D2 Complete Table4.1 to: ● identify a reagent that could distinguish between the compounds in each pair ● give the positive result of the chemical test and identify which compound shows this result. Use a different reagent for each test. C1 has melting point – 94 °C and boiling point + 49 °C. Explain these properties by referring to the type of van der Waals’ forces between molecules. Draw the structure of the cis isomer of C2.  C2 forms a polymer when heated gently. Identify the type of polymer that forms from C2. Draw one repeat unit of the polymer formed from C2.  
13. An introduction to AS Level organic chemistry  →  13.1. Formulas, functional groups and the naming of organic compounds
Open
5
Lactones are cyclic esters. Under suitable conditions, lactones form from molecules that have both an alcohol and a carboxylic acid functional group. Equation1 shows an example of the formation of a lactone. equation 1 + H2O OH OH O O a lactone O Fig.5.1 shows the synthesis of lactoneP from compoundM. O OH HO M N P hot concentrated acidified KMnO4reaction 1 NaBH4 5-hydroxyhexanoic acid reaction 2 reaction 3 M reacts with hot concentrated acidified KMnO4to form N, C6H10O3, in reaction1. Draw the structure of N.  N is reduced by NaBH4 to form 5-hydroxyhexanoic acid in reaction2. Construct an equation for reaction2 using molecular formulae. In the equation, use [H] to represent one atom of hydrogen from the reducing agent. Reaction2 is a nucleophilic addition. Suggest why reaction2 creates a mixture of two organic compounds. Draw lactoneP, the product of reaction3.  A student monitors the progress of reaction2 using infrared spectroscopy. Use Table5.1 to suggest why it is difficult to distinguish between N and 5‑hydroxyhexanoic acid using infrared spectroscopy. Table 5.1 bond functional group containing the bond characteristic infrared absorption range (in wavenumbers) / cm–1 C–O hydroxy, ester 1040–1300 C=C aromatic compound, alkene 1500–1680 C=O amide carbonyl, carboxyl ester 1640–1690 1670–1740 1710–1750 C≡N nitrile 2200–2250 C–H alkane 2850–3100 N–H amine, amide 3300–3500 O–H carboxyl hydroxy 2500–3000 3200–3650 Unknown lactoneQ is analysed using mass spectrometry. Table5.2 shows information from the mass spectrum. Table 5.2 peak m/e abundance M+ 95.5 M+1 3.15 Use these data to deduce the structure of Q. Show your working. Q  
16. Hydroxy compounds  →  16.1. Alcohols
17. Carbonyl compounds  →  17.1. Aldehydes and ketones
Open