Zadanie 1a
Tin and iodine are elements, whereas tin(IV) iodide is a compound. Describe, with reference to these three substances, how an element differs from a compound.
Elements, compounds and mixtures
Tell elements, compounds and mixtures apart by their properties, distinguish homogeneous from heterogeneous mixtures, and choose a separation method (filtration, evaporation, recrystallization, distillation, paper chromatography, solvation) from the physical properties of the components.
Tę umiejętność sprawdza 14 zadań wzorowanych na arkuszach IB z lat 2024–2025.
Zadania sprawdzające tę umiejętność: 14 Otwórz w wyszukiwarce z filtrami
Zadanie 1
A beaker contains a clear, colourless solution of potassium nitrate in water. What is the type of mixture and the best method of obtaining the solid salt from it? A. heterogeneous, by filtration B. heterogeneous, by evaporation C. homogeneous, by filtration D.…
Zadanie 2a
Suggest a sequence of experimental steps that would give a pure sample of each of the three components.
Zadanie 2b
The student recorded the following masses. Calculate the percentage by mass of iron and of calcium carbonate in the mixture.
- Tabela do uzupełnienia
Zadanie 2c
The three percentages in 2b add up to more than 100 %. Suggest an error that would explain this result and how it could be reduced or eliminated.
Zadanie 2d
The results did not support the student's hypothesis. Suggest what the student overlooked when forming the hypothesis.
Zadanie 2e
In a separate experiment, the students needed to separate a mixture of two miscible liquids, ethanol and pentan-1-ol. State the most suitable method of separation and the physical property on which it depends.
Zadanie 1
Which methods for separating the components of the given mixtures are correct? A. I and II only B. I and III only C. II and III only D. I, II and III
- Tabela do uzupełnienia
Zadanie 3f
Explain how the dyes are separated from one another in paper chromatography.
- Materiał graficzny
Zadanie 3a
Describe the steps the student would follow to recrystallize the crude benzoic acid.
Zadanie 3b
State the most important property that water must have, with respect to benzoic acid, for it to be a suitable solvent for this recrystallization.
Zadanie 3c
Outline how each of the two by-products is removed from the benzoic acid during the recrystallization. By-product that is almost insoluble in hot water: ... By-product that is much more soluble than benzoic acid: ...
Zadanie 3d
The volume of hot water used to dissolve the crude solid must be chosen carefully. Deduce the effect on the yield or on the purity of the recrystallized benzoic acid of using too much water and of using too little water. Too much water: ... Too little water:…
Zadanie 1
Which of the following are homogeneous mixtures? I. Dry air II. A mixture of hexane and cyclohexane III. A mixture of oil and water A. I and II only B. I and III only C. II and III only D. I, II and III