11. Group 17
A section of Chemistry, 9701
Listing 10 of 617 questions
The reaction scheme shows some reactions of calcium. CaCa(NO3)2CaOCa(OH)2reaction 1 heat CaCO3+ H2Oreaction 2 CO2CaC2reaction 4 Ca(HCO3)2reaction 3 excess CO2CHNO3 NaOHReaction1 produces Ca(NO3)2 and one other product. Identify the other product. Construct an equation for the thermal decomposition of Ca(NO3)2. State the trend in the thermal stability of the Group2 nitrates down the group. In reaction 3, excess CO2 is bubbled through water containing CaCO3. A solution of Ca(HCO3)2forms. Construct an equation for reaction3. Describe how Ca(OH)2 is used in agriculture. In reaction4, calciumcarbide, CaC2, is formed from CaO. CaC2 contains the C2 2– anion. Each carbon in C2 2– is sp hybridised. Describe how sp hybridised orbitals are formed. Sketch a diagram to show how two sp hybrid orbitals can form a sigma (σ) bond.  The flowchart shows some reactions of CaC2. CaC2 CaCN2 NaCN CaCO3 + NH3 reaction 5 NaCl and C N2 H2O Reaction5 can be used to prepare NH3. CaCN2 + 3H2O → CaCO3 + 2NH3 Calculate the minimum mass, in tonnes, of calciumcyanamide, CaCN2, that is required to produce 1.50×106 tonnes of NH3. Show your working. 1 tonne = 1.00 × 106 g  minimum mass of CaCN2 = tonnes  Draw the structure of the organic products formed in the following reactions. CH3CH2Br NaCN dissolved in ethanol H2SO4heat under reflux NaCN and HCN O  
9701_w21_qp_21
THEORY
2021
Paper 2, Variant 1
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The reaction scheme shows some reactions of calcium. CaCa(NO3)2CaOCa(OH)2reaction 1 heat CaCO3+ H2Oreaction 2 CO2CaC2reaction 4 Ca(HCO3)2reaction 3 excess CO2CHNO3 NaOHReaction1 produces Ca(NO3)2 and one other product. Identify the other product. Construct an equation for the thermal decomposition of Ca(NO3)2. State the trend in the thermal stability of the Group2 nitrates down the group. In reaction 3, excess CO2 is bubbled through water containing CaCO3. A solution of Ca(HCO3)2forms. Construct an equation for reaction3. Describe how Ca(OH)2 is used in agriculture. In reaction4, calciumcarbide, CaC2, is formed from CaO. CaC2 contains the C2 2– anion. Each carbon in C2 2– is sp hybridised. Describe how sp hybridised orbitals are formed. Sketch a diagram to show how two sp hybrid orbitals can form a sigma (σ) bond.  The flowchart shows some reactions of CaC2. CaC2 CaCN2 NaCN CaCO3 + NH3 reaction 5 NaCl and C N2 H2O Reaction5 can be used to prepare NH3. CaCN2 + 3H2O → CaCO3 + 2NH3 Calculate the minimum mass, in tonnes, of calciumcyanamide, CaCN2, that is required to produce 1.50×106 tonnes of NH3. Show your working. 1 tonne = 1.00 × 106 g  minimum mass of CaCN2 = tonnes  Draw the structure of the organic products formed in the following reactions. CH3CH2Br NaCN dissolved in ethanol H2SO4heat under reflux NaCN and HCN O  
9701_w21_qp_23
THEORY
2021
Paper 2, Variant 3
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Pure water is a very poor conductor of electricity. However, when hydrogenchloride gas is dissolved in water, ions are formed and a current flows during electrolysis. HCl + aq → H++ Cl –The overall change after electrolysis is that hydrogenchloride gas is converted into hydrogen and chlorine. 2HCl → H2+ Cl 2When a current of 3.10 A is passed through the solution for Y minutes, 351 cm3 of chlorine are produced at the anode, measured under room conditions. Calculate the number of chlorine molecules produced during the electrolysis.  number of chlorine molecules = Calculate the total number of electrons transferred to produce this number of chlorine molecules.  total number of electrons = Calculate the quantity of charge, in coulombs, of the total number of electrons calculated in .  quantity of charge = C Calculate the time, Y, in minutes, for which the current flows.  Y = minutes The standard entropies, S o, of three species are given in the table. species S o / J K–1 mol–1 HCl +187 H2+131 Cl 2+223 Calculate ∆S o for the reaction 2HCl → H2+ Cl 2. ∆S o = J K–1 mol–1 ∆H o for the reaction 2HCl → H2+ Cl 2is +185 kJ mol–1. Calculate ∆G o for this reaction at 298 K. ∆G o = kJ mol–1 Predict the effect of increasing temperature on the spontaneity of this reaction. Explain your answer.
9701_w21_qp_42
THEORY
2021
Paper 4, Variant 2
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Potassium chlorate, KCl O3, is widely used as an oxidising agent and to make O2. Define oxidising agent. KCl O3decomposes when heated. MnO2catalyses the exothermic decomposition reaction. Complete and label the diagram in to show the effect of MnO2on the decomposition of KCl O3. enthalpy reactants progress of reaction products When KCl O3 is heated without a catalyst, KCl O4 and KCl form. 4KCl O3 3KCl O4 + KCl Explain why this reaction is described as a disproportionation reaction. Molten KCl O3 reacts with glucose, C6H12O6. 4KCl O3 + C6H12O6 6CO2 + 6H2O + 4KCl KCl O3 melts at 630 K. At this temperature, both CO2 and H2O are gases. Use the ideal gas equation to calculate the volume, in m3, of one mole of gas at 630 K and 1.00 × 105 Pa. Show your working. Give your answer to 3 significant figures. volume of 1 mol of gas = m3 5.00 g of C6H12O6 reacts completely with molten KCl O3. Use your answer to to calculate the total volume of gas released at 630 K and 1.00 × 105 Pa in this reaction. (If you were unable to answer , use 0.0463 m3 in this question. This is not the correct answer to .) total volume of gas released = m3 The structure of glucose, C6H12O6, is shown in . OH OH OH HO O OH glucose Complete Table 3.1 to identify the number of primary, secondary and tertiary alcohol groups present in the structure shown in . Table 3.1 type of alcohol group primary secondary tertiary number of groups Separate samples of aqueous glucose are tested with the reagents shown in Table 3.2. Complete Table 3.2 with the observation for each reaction. Write “no reaction” if applicable. Table 3.2 reagent and conditions observation with glucose acidified KMnO4and warm Fehling’s reagent and warm alkaline I2and warm There are many structural isomers of C6H12O6. Define structural isomers.
9701_w23_qp_21
THEORY
2023
Paper 2, Variant 1
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Potassium chlorate, KCl O3, is widely used as an oxidising agent and to make O2. Define oxidising agent. KCl O3decomposes when heated. MnO2catalyses the exothermic decomposition reaction. Complete and label the diagram in to show the effect of MnO2on the decomposition of KCl O3. enthalpy reactants progress of reaction products When KCl O3 is heated without a catalyst, KCl O4 and KCl form. 4KCl O3 3KCl O4 + KCl Explain why this reaction is described as a disproportionation reaction. Molten KCl O3 reacts with glucose, C6H12O6. 4KCl O3 + C6H12O6 6CO2 + 6H2O + 4KCl KCl O3 melts at 630 K. At this temperature, both CO2 and H2O are gases. Use the ideal gas equation to calculate the volume, in m3, of one mole of gas at 630 K and 1.00 × 105 Pa. Show your working. Give your answer to 3 significant figures. volume of 1 mol of gas = m3 5.00 g of C6H12O6 reacts completely with molten KCl O3. Use your answer to to calculate the total volume of gas released at 630 K and 1.00 × 105 Pa in this reaction. (If you were unable to answer , use 0.0463 m3 in this question. This is not the correct answer to .) total volume of gas released = m3 The structure of glucose, C6H12O6, is shown in . OH OH OH HO O OH glucose Complete Table 3.1 to identify the number of primary, secondary and tertiary alcohol groups present in the structure shown in . Table 3.1 type of alcohol group primary secondary tertiary number of groups Separate samples of aqueous glucose are tested with the reagents shown in Table 3.2. Complete Table 3.2 with the observation for each reaction. Write “no reaction” if applicable. Table 3.2 reagent and conditions observation with glucose acidified KMnO4and warm Fehling’s reagent and warm alkaline I2and warm There are many structural isomers of C6H12O6. Define structural isomers.
9701_w23_qp_23
THEORY
2023
Paper 2, Variant 3
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Benzene reacts with chlorine gas to form chlorobenzene. This reaction can be described as the reaction between benzene molecules and Cl + ions. The Cl + ions are formed by adding a suitable catalyst to the chlorine gas. Give the name or formula of a catalyst that can be used for this reaction. The mechanism for this reaction is shown. Cl + Cl Cl x y step 1 step 2 diagram 1 diagram 2 diagram 3 H + The movement of a pair of electrons is represented by x in diagram 1. • State where this pair of electrons is before step 1 takes place. • State where this pair of electrons is after step 1 has taken place. The movement of another pair of electrons is represented by y in diagram 2. • State where this pair of electrons is before step 2 takes place. • State where this pair of electrons is after step 2 has taken place. There are six carbon atoms in diagram 2. State how many of these carbon atoms are sp hybridised, sp2 hybridised, and sp3 hybridised. sp hybridised sp2 hybridised sp3 hybridised Complete the equation for this reaction between benzene and chlorine. C6H6 + + The mechanism for this reaction is electrophilic substitution. Complete the following sentence. Write formulae in the gaps provided. During this reaction, the electrophile is and a atom in benzene is substituted by a atom. Chloroethane reacts with NaOH. Chlorobenzene does not. Name the mechanism of the reaction that chloroethane undergoes with NaOH, and identify the major organic product that is formed. mechanism major organic product Explain the difference in reactivity of chloroethane and chlorobenzene when treated with NaOH.
9701_w24_qp_42
THEORY
2024
Paper 4, Variant 2
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