wzorowane2 pktotwartełatwe (szac.)
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.
Zadania sprawdzające tę umiejętność: 13 Otwórz w wyszukiwarce z filtrami
wzorowane1 pktzamkniętełatwe (szac.)
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.…
wzorowane4 pktotwarteśrednie (szac.)
Suggest a sequence of experimental steps that would give a pure sample of each of the three components.
wzorowane1 pktobliczeniowełatwe (szac.)
The student recorded the following masses. Sample Mass / g (± 0.01 g) Percentage by mass Mixture before separation 6.35 not applicable Iron after separation 2.58 Calcium carbonate after separation 1.71 Potassium chloride after separation 2.31 36.4 % Calculate…
wzorowane2 pktotwarteśrednie (szac.)
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.
wzorowane1 pktotwarteśrednie (szac.)
The results did not support the student's hypothesis. Suggest what the student overlooked when forming the hypothesis.
wzorowane2 pktotwartełatwe (szac.)
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.
wzorowane1 pktzamkniętełatwe (szac.)
Which methods for separating the components of the given mixtures are correct? Mixture Method I. Two miscible liquids with boiling points of 56 °C and 118 °C Distillation II. The coloured pigments extracted from a leaf Paper chromatography III. A solid…
wzorowane2 pktotwarteśrednie (szac.)
Explain how the dyes are separated from one another in paper chromatography.
wzorowane3 pktotwarteśrednie (szac.)
Describe the steps the student would follow to recrystallize the crude benzoic acid.
wzorowane1 pktotwartełatwe (szac.)
State the most important property that water must have, with respect to benzoic acid, for it to be a suitable solvent for this recrystallization.
wzorowane2 pktotwarteśrednie (szac.)
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: ...
wzorowane2 pktotwarteśrednie (szac.)
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:…