Calcite is a mineral which contains mainly calcium carbonate.An experiment, consisting of the following five stages,was conducted to determine the percentage by mass of calcium carbonate in a sample of calcite.
Stage 1:Weigh the sample.Add dilute nitric acid to it until the acid is in excess.
------->suggest how one can know that excess acid has been added in stage 1
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2008-03-09 11:14 pm
回答 (1)
2008-03-09 11:46 pm
✔ 最佳答案
Add dilute nitric acid to calcite drop by drop until calcite does not evolve colorless gas bubbles anymore.And the colorless gas bubbles are carbon dioxide.
The chemical reaction goes like that,
2 HNO3 CaCO3 -> Ca(NO3)2 CO2 H2O
If too much nitric acid is added, there should be no more calcium carbonate to react with the excess nitric acid to evolve colorless carbon dioxide gas bubbles because all calcium carbonate is turned into calcium nitrate.
參考: myself
收錄日期: 2021-04-23 19:49:26
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