1 (b) M is an element that belongs to the 3rd period of the periodic table and is a member of the alkaline earth metals. Show the position of M in the grid.
This chemistry question involves key chemical concepts and calculations. The detailed solution below walks through each step, from identifying the reaction type to computing the final answer.
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1 (b) M is an element that belongs to the 3rd period of the periodic table and is a member of the alkaline earth metals. Show the position of M in the grid.
The element M is Magnesium (Mg).
It is located in Group 2, Period 3 of the periodic table.
2 (a) The diagram below shows spots of pure substances A, B and C on a chromatography paper. Spot D is that of a mixture. After development A, B and C were found to have moved 8cm, 3cm and 6cm respectively. D was separated into two spots which had moved 6cm and 8cm.
(i) On the diagram:
(I) Label the baseline (origin)
The baseline (origin) is the horizontal line at the bottom of the chromatography paper where the initial spots A, B, C, and D were applied. It is marked by the 'X' symbols.
(II) Show the positions of all the spots after development
• Spot A: Mark a spot at the 8 cm line above the origin, directly above the initial 'X' for A.
• Spot B: Mark a spot at the 3 cm line above the origin, directly above the initial 'X' for B.
• Spot C: Mark a spot at the 6 cm line above the origin, directly above the initial 'X' for C.
• Spot D: Mark two spots above the initial 'X' for D: one at the 6 cm line and another at the 8 cm line.
(ii) Identify the substances present in mixture D
Mixture D separated into two spots that moved 6 cm and 8 cm.
Substance C moved 6 cm.
Substance A moved 8 cm.
Therefore, mixture D contains substances A and C.
2 (b) Describe how solid ammonium chloride can be separated from a solid mixture of ammonium chloride and anhydrous calcium chloride.
This separation can be achieved by sublimation.
Step 1: Place the solid mixture of ammonium chloride and anhydrous calcium chloride in an evaporating dish.
Step 2: Gently heat the evaporating dish. Ammonium chloride will sublime, turning directly from a solid into a gas.
Step 3: Place an inverted funnel or watch glass over the evaporating dish. The ammonium chloride vapor will cool and solidify (deposit) on the cooler surface of the funnel/watch glass, forming pure solid ammonium chloride.
Step 4: The anhydrous calcium chloride, which does not sublime, will remain in the evaporating dish.
