Zadanie 1a
Outline why a large number of the elements in the table have atomic volumes above 10 000 cm3 mol−1.
Chemistry HL Paper 3, May 2023, TZ2
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Dodaj cały arkusz do zestawuZadanie 1b
Outline why some of these elements have atomic volumes close to 11 350 cm3 mol−1 while others have values close to 22 700 cm3 mol−1.
Zadanie 1c
Phosphorus and oxygen each have a second value in the last column of the table. Suggest why a single element can have two different atomic volumes.
Zadanie 1d
Explain the steady fall in atomic volume from element 11 to element 13.
Zadanie 1e
Estimate the atomic volume, in cm3 mol−1, of element 20.
Zadanie 1f
Suggest, giving one reason, whether the volume of a single atom could ever be known exactly.
Zadanie 2a
All the species in the titration are almost colourless except MnO4−, which is intensely purple. The spinach extract, however, is coloured green by chlorophyll. (i) State the colour change at the end point. (ii) Outline how adding distilled water to the…
Zadanie 2b
State the class of error that always shifts the results of an experiment in the same direction.
Zadanie 2c
The end point was reached after 3.0 ± 0.1 cm3 of titrant had been run in. (i) Calculate the percentage uncertainty in this titre. (ii) Suggest one change to the procedure that would lower the percentage uncertainty of a single titration, apart from…
Zadanie 2d
The result is roughly 30 times higher than the iron content of spinach given in reference tables (as a percentage by mass). Suggest one reason, apart from human error, for so large a difference.
Zadanie 3b
Beryllium metal is produced by the electrolysis of beryllium chloride, BeCl2, dissolved in molten sodium chloride. (i) Write the half-equation for the process at the electrode where beryllium metal is produced. (ii) Calculate the atom economy of this…
Zadanie 3d
Graphene, a single layer of carbon atoms, is used to reinforce plastics and metals. Outline why graphene is so strong and rigid.
Zadanie 4a
A section of an addition polymer chain, made from a single monomer, is shown. Draw the structural formula of the monomer that polymerizes to give this chain.
- Materiał graficzny
Zadanie 4e
Polylactic acid (PLA), a biodegradable plastic, is formed from the monomer lactic acid, shown. State the type of polymerization by which PLA forms and the structural feature of lactic acid that makes this type of polymerization possible.
- Materiał graficzny
Zadanie 4f
Outline, in terms of their structure, why polyethene carrier bags remain in landfill sites for many decades.
Zadanie 5c
Copper(II) ions can be removed from waste water by chelation. A possible ligand is the nitrilotriacetate anion, shown. Identify the atoms in the ligand that form coordination bonds with a copper(II) ion when it forms a complex ion.
- Materiał graficzny
Zadanie 7b
A student separates the coloured dyes in a sample of black ink by paper chromatography, using water as the solvent. Explain how paper chromatography can separate and identify the dyes in a mixture.
Zadanie 7d
A student prepared standard solutions of copper(II) sulfate and measured the absorbance of each with a colorimeter. The graph shows the calibration line. A sample of copper(II) sulfate solution of unknown concentration has an absorbance of 0.600. State its…
- Materiał graficzny
Zadanie 13b
4-Nitrophenol can act as an acid-base indicator. Its acid form, HIn, is colourless and its conjugate base, In−, is yellow. Explain how 4-nitrophenol acts as an acid-base indicator as the pH increases.
- Materiał graficzny
Zadanie 15a
(i) Write the balanced equation for photosynthesis, in which glucose is formed. (ii) Explain how the large-scale planting of fast-growing trees is intended to reduce the rate of global warming.
Zadanie 15d
Both hydrogen and methanol can be used as fuels in fuel cells. Outline one way in which a fuel cell differs from a primary (voltaic) cell.
Zadanie 16a
Methane, the main component of natural gas, burns in a domestic boiler. State the main form of energy released directly by the combustion reaction.
Zadanie 16c
Hexane is a component of petrol. The equation for its combustion is: Determine the mass of carbon dioxide, in g, released for every 1 kJ of energy produced by the combustion of hexane. Use section 14 of the data…
Zadanie 22a
Magnesium hydroxide is the active ingredient of some indigestion remedies, which neutralize excess hydrochloric acid in the stomach. (i) Write an equation for the reaction of magnesium hydroxide with hydrochloric acid. (ii) Calculate the mass, in g, of…
Zadanie 27a
Propan-1-ol can be identified by a variety of analytical techniques. Predict the structures of three possible fragments you would expect from the mass spectrum of propan-1-ol. Use section 22 of the data booklet.
Zadanie 27b
Propan-1-ol is heated under reflux with an excess of acidified oxidizing agent. Identify the two organic compounds formed, one after the other, in the course of the oxidation.