10. Group 2
A section of Chemistry, 9701
Listing 10 of 275 questions
What is meant by the density of a substance? Use data from the Data Booklet to explain why the density of iron is greater than that of calcium. In general, reactions of the compounds of transition elements can be classifi ed under one or more of the following headings. acid-base ligand exchange precipitation redox Choose the most suitable heading to describe each of the following reactions, by placing a tick ( ) in the appropriate column in the table below. Only one tick should be placed against each reaction. reaction acid-base ligand exchange precipitation redox [Cu(H2O)6]2+ + 4NH3 → [Cu(NH3)4]2+ + 6H2O [Cu(H2O)6]2+ + 4HCl → [CuCl 4]2– + 4H+ + 6H2O 2FeCl 2 + Cl 2 → 2FeCl 3 [Fe(H2O)6]2+ + 2OH– → Fe(OH)2 + 6H2O 2Fe(OH)2 + ½O2 + H2O → 2Fe(OH)3 CrO3 + 2HCl → CrO2Cl 2 + H2O Cr(H2O)3(OH)3 + OH– → [Cr(H2O)2(OH)4]– + H2O [Cr(OH)4]– + 1½H2O2 + OH– → CrO4 2– + 4H2O  Alloys of aluminium, titanium and vanadium are used in aerospace and marine equipment, and in medicine. When a powdered sample of one such alloy is heated with an excess of aqueous NaOH, only the aluminium reacts, according to the following equation. 2Al + 2OH–+ 6H2O→ 2[Al (OH)4]–+ 3H2Reacting 100 g of alloy in this way produced 8.0 dm3 of hydrogen, measured under room conditions. Calculate the percentage by mass of aluminium in the alloy. percentage = %
9701_s13_qp_41
THEORY
2013
Paper 4, Variant 1
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What is meant by the density of a substance? Use data from the Data Booklet to explain why the density of iron is greater than that of calcium. In general, reactions of the compounds of transition elements can be classifi ed under one or more of the following headings. acid-base ligand exchange precipitation redox Choose the most suitable heading to describe each of the following reactions, by placing a tick ( ) in the appropriate column in the table below. Only one tick should be placed against each reaction. reaction acid-base ligand exchange precipitation redox [Cu(H2O)6]2+ + 4NH3 → [Cu(NH3)4]2+ + 6H2O [Cu(H2O)6]2+ + 4HCl → [CuCl 4]2– + 4H+ + 6H2O 2FeCl 2 + Cl 2 → 2FeCl 3 [Fe(H2O)6]2+ + 2OH– → Fe(OH)2 + 6H2O 2Fe(OH)2 + ½O2 + H2O → 2Fe(OH)3 CrO3 + 2HCl → CrO2Cl 2 + H2O Cr(H2O)3(OH)3 + OH– → [Cr(H2O)2(OH)4]– + H2O [Cr(OH)4]– + 1½H2O2 + OH– → CrO4 2– + 4H2O  Alloys of aluminium, titanium and vanadium are used in aerospace and marine equipment, and in medicine. When a powdered sample of one such alloy is heated with an excess of aqueous NaOH, only the aluminium reacts, according to the following equation. 2Al + 2OH–+ 6H2O→ 2[Al (OH)4]–+ 3H2Reacting 100 g of alloy in this way produced 8.0 dm3 of hydrogen, measured under room conditions. Calculate the percentage by mass of aluminium in the alloy. percentage = %
9701_s13_qp_43
THEORY
2013
Paper 4, Variant 3
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