Научный журнал
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- Experiment 5
| Experiment 4 Interaction of metals with solutions of salts.
The zinc plate is lowered by the teacher into a solution of copper (II) sulphate. In a test tube, on the walls of which, after carrying out the reaction of the «silver mirror», silver settled, adds a saturated solution of copper (II) chloride. Aluminum granules are dipped into a solution of sodium carbonate and heated. Schoolchildren explain the processes occurring and record the reaction equations in self-control sheets. The teacher demonstrates a slide with the correct reaction equations. Students correct mistakes with red pens The teacher tells how to determine the presence of metal ions in salt solutions. When using the dry method, the dry salt is ground in a mortar with a detectable substance. The wet method consists in draining the solutions and determining the presence of an ion by external features. Pyrochemical method – the determination of ions by staining the flame with solutions of metal salts. Experiment 5 Determination of metal cations in salt solutions. The teacher rinses the nichromic wire in 20 % hydrochloric acid and dries. Then the tip of it (ringlet) in turn drops into concentrated solutions of salts of calcium, sodium, copper, potassium, better – chlorides (they are more volatile) and brings into the flames of alcohol lamps. Salts should be dissolved in distilled water, since the presence of sodium salts in tap water interferes with the observation of flame coloration by other cations. Task 5 Conclusion on the properties of metals. Fill in the gaps with the words you need. The radius of the atoms of metals is ______ than the radius of the atoms of nonmetals.. In all compounds metals have _____ degree of oxidation. At room temperature, metals are ______ aggregate state, with the exception of ____. Metals have a characteristic _____. They are good at _____ and _____. The heaviest metal is _____, the easiest is _____, the most refractory is _______, the most fusible is _____. In conclusion, the teacher summarizes the lesson and invites students to conclude on this topic. On the slide, the answers are correctly shown, the students correct the errors with a red pen and make themselves mark on the subject, fill in the reflection. жүктеу/скачать 3.75 Mb. Достарыңызбен бөлісу:
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