Edexcel IAL Chemistry 8.18 Group 1 and 2 experimental procedures

Specify the cleaning and heating method, record the exact flame or gas observation and pair each gas with its positive test before judging procedural limitations.

Exam points

Describe flame testing with hydrochloric acid, a clean support and a non-luminous flame.
Identify NO₂, O₂ or CO₂ from colour, splint, limewater or acidity evidence.
Compare thermal decomposition using controlled heating, gas tests and apparatus limitations.

[Maximum number: 5]

This question is about the element calcium and some of its compounds.

(a)

A sample of solid anhydrous calcium nitrate, $\mathrm{Ca}\left(\mathrm{NO}_{3}\right)_{2}(\mathrm{~s})$ , is heated strongly for several minutes in the apparatus shown.

Figure for Question (a) — Edexcel A-Level Chemistry AS

[ 5 ]

(i)

State two observations that would be made.

1

2

[ 2 ]

(ii)

Explain why the observations from (c)(i) would be made more quickly if the experiment was repeated with solid anhydrous magnesium nitrate, $\mathrm{Mg}\left(\mathrm{NO}_{3}\right)_{2}(\mathrm{~s})$ .

[ 3 ]

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8.18—Experimental procedures to show: i patterns in the thermal decomposition of Group 1 and 2 nitrates and carbonates Students question 1

Question (a)

Question (i)

Question (ii)