Zadanie 1a
Deduce the oxidation state of bromine in the reactant and in each of the two products. Reactant Br2: Product HOBr: Product HBr:
Chemistry SL Paper 1B, specimen 2025
Zadania wzorowane na pytaniach z tego arkusza: te same umiejętności, format i punktacja, inne dane i kontekst. Treści arkusza IB nie publikujemy.
W bazie 12 zadań z tego arkusza, razem 25 punktów, każde z kluczem i schematem punktowania. Najwięcej zadań sprawdza: Le Chatelier's principle (4), Units, uncertainties and graphs (3), Exploring and designing investigations (3).
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Dodaj cały arkusz do zestawuZadanie 1b
When sodium hydroxide solution is added to the water, a larger amount of bromine reacts. Explain this observation.
Zadanie 1c
A student compiles data on the solubility of bromine in water at different temperatures from several websites and textbooks. (i) Identify one problem that arises when the values from these sources are compared with one another. (ii) Each solubility is then…
- Tabela do uzupełnienia
Zadanie 1d
Suggest why hot-tub owners rarely add bromine itself to the water and instead use solid tablets that release HOBr.
Zadanie 1e
In water, HOBr partly ionizes to give the hypobromite ion, OBr−; the ion is a much weaker sanitizer than the un-ionized acid. The graph shows how the percentages of the dissolved bromine present as HOBr(aq) and as OBr−(aq) vary with pH at 25 °C.…
- Materiał graficzny
Zadanie 1f
Ammonia from sweat and skin-care products reacts with HOBr to form bromamines: NH2Br, NHBr2 and NBr3. (i) Deduce an equation for the reaction of ammonia with HOBr(aq) that produces dibromamine, NHBr2(aq). (ii) The graph shows how…
- Materiał graficzny
Zadanie 1g
Hot tubs are usually kept at 38–40 °C. Suggest two reasons why running a hot tub at a lower temperature would be better for the environment.
Zadanie 2a
Identify two controlled variables in this investigation.
- Materiał graficzny
Zadanie 2b
The iron(II) concentration is found by titrating against a standard solution of potassium manganate(VII), KMnO4. At intervals of a few days, a 20.00 cm3 sample is withdrawn from each flask and made up to 250.0 cm3 with water;…
- Materiał graficzny
Zadanie 2c
The following readings are recorded during one titration. Final burette reading = 23.20 ± 0.05 cm3 Initial burette reading = 3.20 ± 0.05 cm3 Calculate the percentage uncertainty in the volume of KMnO4 solution delivered…
- Materiał graficzny
Zadanie 2d
The student's results are shown in the graph. (i) Calculate the average rate at which the iron(II) concentration fell in the 24 h flask during the 21 days. Include units. (ii) Before starting, the student proposed the hypothesis: "The longer a solution is left…
- Materiał graficzny
Zadanie 2e
Suggest one way of extending the investigation so that further recommendations about storing the iron(II) solution could be made.
- Materiał graficzny