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Date Submitted: 12/26/2010 01:34 AM
Exercise N°1: Careful Observation
1st Report
Zg. Polskava, 7 September 2009
Aim
The aim of the experiment is to emphasize the importance of carefulness of the observations during experiments.
Experiments
1. Adding a few drops of silver nitrate solutions to a test tube containing 2 or 3 cm3 of sodium chloride solutions.
2. Dropping a provided piece of magnesium into a test tube containing 2 or 3 cm3 of dilute sulphuric acid.
3. Dropping the piece of zinc provided into 5 cm3 of copper(II) sulphate solution, warming the mixture and letting it stand for five minutes.
4. Heating a spatula measure of copper(II) carbonate in a test tube.
5. Adding a few drops of dilute hydrochloric acid to a test tube containing about 5 cm3 of sodium thiosulphate solution and letting the mixture stand for several minutes.
6. Heating a piece of magnesium ribbon in Bunsen flame, using tongs.
7. Mixing approximately 5cm3 of dilute hydrochloric acid with approximately 5 cm3 of sodium hydroxide solution in a test tube.
8. Heating half a spatula measure of ammonium chloride in a test tube.
Observations
|N° of Experiment |Changes |
|1 |white precipitate |
|2 |formation of bubbles |
|3 |turning brown, precipitation |
|4 |changing colour into black, foul odour |
|5 |becoming opaque, yellow |
|6 |white flame, substance turning to white powder |
|7 |becoming opaque |
|8 |sublimation |
Table 1: Changes in colour in different test tubes....