Zadanie 1a
Outline why a large number of the elements in the table have atomic volumes above 10 000 cm3 mol−1.
Chemistry SL 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.
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Zadanie 4e
Outline, in terms of their structure, why polyethene carrier bags remain in landfill sites for many decades.
Zadanie 6b
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 8b
Glucose, C6H12O6, is a monosaccharide that is oxidized in the body to carbon dioxide and water. The standard enthalpy change of combustion of glucose is −2803 kJ mol−1. Calculate the energy, in kJ, released by the complete combustion of…
Zadanie 11a
(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 12a
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 12c
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 18a
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…