chemistry lesson

Hydrolysis of organic substances-DISPERSED SYSTEMS. SOLUTIONS. PROCESSES OCCURRING in SOLUTIONS - LESSON DEVELOPMENTS in CHEMISTRY grade 11 - lesson developments-lesson developments - author's lessons - lesson plan-lesson summary - chemistry

The purpose of the lesson: to summarize information about the hydrolysis of organic substances; based on the concept of "hydrolysis" to show the unity of the world of organic and inorganic substances; to expand the understanding of the meaning of hydrolysis of organic substances in living nature and society.

Basic concepts: hydrolysis, esters, carbohydrates,proteins-biopolymers, adenosine triphosphoric acid, amino acids.

Equipment for the experiment: solutions of Na₂, SO_{3, ZnCl 2 , So 3 salts in test tubes № 1 , 2,}3₂, NaNО₃; indicators: universal indicator, phenolphthalein, blue litmus, methyl orange.

Lesson progress

I. Organizational moment

The lesson combined. The lesson provides for a survey, an experiment of students at the time of a monologue answer. When studying a new material, you can work with a textbook, make a table in a notebook.

II. Checking students ' knowledge

1. Monologue response of students at the blackboard with the implementation of the experiment. Determine the reaction of the medium of solutions of salts Na₂SO₃; XnCl₂;_{So 3}indicators. Give a reasonable answer.

2. Homework # 3 (two salts).

3. Homework assignment # 4 (two salts).

All other students discuss completing task # 5.

At the end of the homework check, offer students a question on the use test:

1) Water solutions of which salt pair have the same reaction (acid, alkaline, neutral)?

2) Match the dissolved substance with the pH of the solution:

Answers to the knowledge verification questions

Task # 1. Experiment. Layout in the form of a table.

The teacher analyzes the correct execution and design of the experiment, warns that the next lesson will be a practical work on the topic "Hydrolysis.Ion exchangereagents".

Task # 2. salts formed by a weak base and a strong acid are subjected to Hydrolysis by cation. Among the proposed salts is Cu(NO₃)₂, NH₄NO₃, NiSO₄:

Task # 3.salts formed by a strong base and a weak acid are subjected to Hydrolysis by anion. Of the proposed salts, this is Na₂SO₃, K(NSOO):

The task № 4

Salts formed by strong bases and strong acids do not undergo hydrolysis. The medium in these solutions is neutral.

Tasks for the unified state exam tests

1. Aqueous solutions of substances of vapor No. 1 have a neutral reaction of solutions, since they themselves are formed by a strong base and a strong acid. There is no hydrolysis. KNO₃( CON, HNO₃), NaCl(NaOH, HCl). If we consider pairs:

No. 2. Na₂CO₃, FeCl₃, then in solution:

Na₂CO₃-alkaline medium,

FeCl₃-acidic medium.

№ 3. Na₂SO₄, Cu(NO₃)₂:

Na₂SO₄-neutral medium,

Cu(NO₃)₂— the acidic environment.

No. 4. Aug₂, АlВr₃:

Vavg₂-neutral medium,

ALVR₃-acidic medium.

2. Weakly alkaline-NH_{3 solution}; 1-G;

Strongly acidic-solution H₂SO₄; 2-D;

Neutral — a solution of Ba(NO₃)₂; 3-In;

Weak acid-solution NH₄Cl; 4-B;

Strongly alkaline-a solution of KOH; 5-A.

III. Learning new material

Students 'work with the text of § 16 p. 158-161 and completing the table "Hydrolysis of organic compounds and its practical significance".

Thus, hydrolysis is also characteristic of most organic substances — this is their most important organic property. However, in these cases, water is a reagent, and not necessarily one of the products — a weak electrolyte, as in the hydrolysis of inorganic substances, and the solution medium does not always change.

Hydrolysis of organic substances is also a reversible process, the onset of chemical equilibrium is possible, and it is necessary to know the conditions for its displacement according to the Le Chatelier principle.

It should be remembered that the study of the theoretical foundations of hydrolysis requires knowledge not only of previously studied questions of the chemistry course, but also questions of the biology course, especially metabolism in a living organism.

IV. Homework assignment

§ 16, preparation for practical work, repetition § 15, № 7, 8, 11, 12.