Development of a lesson on the topic: "Chemical properties of metals"
Lesson goal: To consider the general chemical properties of metals
Lesson Objectives:
To characterize the most important chemical properties of metals;
Using the example of reactions characterizing chemical properties, repeat the types of chemical reactions
Continue developing the ability to work with laboratory equipment.
During the classes
1. Organizational moment
Greetings from students. Checking readiness for the lesson. Communication of the topic and purpose of the lesson.
Task for group number 1
Writing a mini - test with an open - ended answer. One student works at the blackboard (but until the moment of checking his answers are not visible to the class), the rest of the student groups work in notebooks.
Options for questions:
The ability of a substance to change its shape under external influence and maintain it after the cessation of exposure? (plastic);
What is the type of chemical bond in metals? (metal);
What mobile particles of the crystal lattice provide the physical properties of metals? (electrons);
What is the density of light metals (less than 5 g / cm3);
The lightest metal? (lithium);
The best conductors of electricity among metals? (silver and copper);
The name of a well-known aluminum-based alloy (duralumin);
The most important iron-based alloys? (cast iron and steel);
What non-metal is part of iron alloys (carbon);
Indicate at least three metals that can act as alloying additives? (chrome, nickel, molybdenum)
Task for group number 2
Solving the problem on the topic "Alloys":
A bronze monument to Minin and Pozharsky has been erected on Red Square. The mass of the monument is 16 tons. Determine the mass of copper that was spent on the creation of this monument.
Task for group number 3.
The team receives a sample of the metal that needs to be characterized for physical properties and approximate applications.
The task is given no more than 5 minutes. Then the results are checked.
Practical task for all groups: Write the reaction equations: Fe2O3- Ca (FeO2) 2- Fe2 (SO4) 3- Fe (NO3) 3- Fe (OH) 3- Fe2O3
3. Formation of new knowledge.
The teacher speaks out the main tasks of the lesson (the principle of goal-setting):
We must conclude the lesson:
* know the general chemical properties of metals;
* be able to write down the reaction equations characterizing the chemical properties of metals;
* get the skills of carrying out chemical reactions.
It is relevant to ask students the question: "Why is it necessary to know the chemical properties of metals?"
When explaining the material, a presentation with video fragments of the experiments is used.
Chemical properties of metals
The explanation of the new material is presented in the form of an active dialogue with the students, since part of the educational material, namely: the principles of writing chemical equations, the properties of acids and salts, signs and types of chemical reactions, the rules of a number of metal voltages, OVR processes are known to them. Thus, in the course of studying new material, a number of topics of the course of chemistry for the 8th grade are consolidated.
1. Interact with non-metals.
A video clip is watched and the reaction equation is recorded. For example: burning magnesium: 2Mg + O2 = 2MgO. The processes of oxidation - reduction are analyzed.
2. Interaction with water.
Alkali and alkaline earth metals actively react with water. The reaction is analyzed using sodium as an example: 2Na + 2H2O = 2NaOH + H2
The reaction of a less active metal with water is analyzed using iron as an example.
3Fe + 4H2O = Fe3O4 + 4H2
3. Interaction with acids
taking into account the rules for the position of metals in the voltage series
K Ca Na Mg Al Zn Fe Ni Sn Pb H2 Cu Hg Ag Au
The metal in the row must be up to hydrogen (does not apply to alkali and alkaline earth metals);
The resulting salt must be soluble;
Nitric and concentrated sulfuric acids react with metals in a special way.
Further, video fragments of the interaction of aluminum with hydrochloric acid and copper with concentrated nitric acid are viewed and the equations of these reactions are written.
2Al + 6HCl = 2AlCl3 + 3H2
Cu + 4HNO3 = Cu (NO3) 2 + 2NO2 + 2H2O
4. Interaction with salts
taking into account the rules for the position of metals in the voltage series
K Ca Na Mg Al Zn Fe Ni Sn Pb H2 Cu Hg Ag Au
The metal in the row must stand up to the metal of the salt (does not apply to alkali and alkaline earth metals);
All salts involved in the reaction must be soluble
A video fragment of the interaction of zinc with copper (II) chloride is watched and the students write down the reaction equation:
Zn + CuCl2 = ZnCl2 + Cu
General conclusion on the stage of the formation of new knowledge:
Metals react:
* With non-metals
* With water (subject to conditions)
* With acids (taking into account the rules of a number of metal voltages)
* With salts (taking into account the rules of a number of metal voltages)
4. Consolidation of the studied material
At the stage of consolidation, students are invited to perform laboratory work to study the chemical properties of metals.
Interaction of copper with oxygen;
Interaction of zinc with hydrochloric acid;
The interaction of iron with a solution of copper (II) sulfate
The work is done in pairs, the results are commented and written in a notebook.
5. Summing up (reflection)
A) What have I learned about the chemical properties of metals?
B) Why is it necessary to know the chemical properties of metals?
C) What could you suggest for better assimilation of the material on this topic?
