HardChemistryHigh School (11–12)Organic Chemistry: Some Basic Principles and Techniques › Purification and Analysis of Organic CompoundsNumericalA-LevelIBNEET
A 0.175 g sample of a compound holds 16 % nitrogen by mass…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
A sample of a compound holds nitrogen by mass. All the nitrogen turns into cyanide ions in the extract. Find the amount of cyanide, and the largest mass of Prussian blue, , with a molar mass of , that it could make. Eighteen cyanide ions go into one unit of Prussian blue.
Need a reminder? The key ideaShow
Carbon is shown by carbon dioxide turning lime water milky, and hydrogen by water turning white copper sulphate blue. Fusion with sodium turns N, S and the halogens into CN, S and X ions. Nitrogen: Prussian blue. Sulphur: black PbS or violet with nitroprusside. Nitrogen and sulphur together: blood red . Halogens: boil with nitric acid first, then silver nitrate. Phosphorus: a yellow colour with ammonium molybdate.
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. Nitrogen. .
Step 2. Cyanide. , which is .
Step 3. Units of Prussian blue. .
Step 4. Mass. .
Answer: of cyanide, and at most of Prussian blue.
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