Zadanie 1a
Identify the independent variable and the dependent variable in this investigation.
- Materiał graficzny
Chemistry HL Paper 1B, May 2026, TZ2
Zadania wzorowane na pytaniach z tego arkusza: te same umiejętności, format i punktacja, inne dane i kontekst. Treści arkusza IB nie publikujemy.
Dodaj cały arkusz do zestawuZadanie 1b
State two variables that should have been kept constant in the four runs.
- Materiał graficzny
Zadanie 1c
Discuss the range of the independent variable and the quantity of data in this investigation.
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Zadanie 1d
Suggest why the light intensity rose during the first minutes of each run.
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Zadanie 1e
Suggest how the total quantity of light emitted in each run could be obtained from the graph.
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Zadanie 1f
Explain how the rate at which the light intensity was falling after 15 minutes in the 44.8 °C run could be determined from the graph.
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Zadanie 1g
The graph shows the maximum rate of decrease in light intensity for each run, plotted against temperature. (i) Draw the best-fit curve on the graph. (ii) Suggest two possible conclusions that can be drawn from the investigation.
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Zadanie 1h
Suggest two modifications to the procedure that would make the data more reliable.
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Zadanie 2a
Calculate the change in temperature for trial 5 and its uncertainty. Give the temperature change to a suitable number of decimal places and the uncertainty to a suitable number of significant figures.
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Zadanie 2b
The student decided to ignore the uncertainty in the mass of ethanol burnt when calculating the specific energy. Discuss whether this decision is valid, using the percentage uncertainties for trial 5.
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Zadanie 2c
Calculate the specific energy of ethanol for trial 5, in J g−1. Use sections 1 and 2 of the data booklet. mwater = 120.0 g
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Zadanie 2d
Determine the mean specific energy of ethanol from the five trials, explaining your method. If you did not obtain an answer to (c), use 8000 J g−1 for trial 5; this is not the correct value.
- Tabela do uzupełnienia
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Zadanie 2e
Calculate the percentage error in the mean specific energy of ethanol. Literature value of the specific energy of ethanol = 29.7 kJ g−1
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Zadanie 2f
Suggest two ways in which the error in this experiment could be reduced.
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Zadanie 3a
Outline why a standard solution of potassium manganate(VII) was needed for this analysis.
Zadanie 3b
Suggest why diluting the standard solution was necessary.
Zadanie 3c
State two items of glassware that the dilution required.
Zadanie 3d
The titration was carried out using a burette, a volumetric pipette and a conical flask. State which of the three items should be rinsed with the solution it will hold, and which only with distilled water.
Zadanie 3e
(i) The diagram shows the burette scale at the end of trial 4. The solution is deep purple, so the reading is taken at the top of the liquid. Determine the final burette reading for trial 4 and complete the table. (ii) Suggest, with a reason, whether more…
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Zadanie 3f
Colorimetry is an alternative technique for determining concentration. Iron(II) ions can be converted to a red complex ion by adding 1,10-phenanthroline. (i) Outline why the concentration of iron(II) in a solution can be measured by colorimetry after this…