Home Mushrooms A burning candle was placed in the jar and the jar was closed. Examination in chemistry on the topic "Non-metals" (grade 9). IV Consolidation of the studied material

Mushrooms

A burning candle was placed in the jar and the jar was closed. Examination in chemistry on the topic "Non-metals" (grade 9). IV Consolidation of the studied material

Lesson form: research with elements of interdisciplinary integration.

You cannot change someone by transferring a ready-made experience to him.
You can only create an atmosphere conducive to human development.
K. Rogers

The purpose of the lesson: look at the flame of a candle and at the candle itself through the eyes of a researcher.

Lesson Objectives:

To begin the formation of the most important method of cognizing chemical phenomena - observation and the ability to describe it;

Show in the course of practical work the significant differences between physical and chemical reactions;

To update the basic knowledge about the combustion process, taking into account the material learned in the lessons of other academic disciplines;

Illustrate the dependence of the reaction of burning a candle on the conditions of the reaction;

To begin the formation of the simplest techniques for conducting qualitative reactions to detect the products of candle combustion;

Develop cognitive activity, observation, broaden horizons in the field of natural science and artistic and aesthetic knowledge of reality.

Lesson steps:

I Organizational moment. Introductory speech of the teacher.

Candle? - a traditional lighting fixture, which is most often a cylinder of solid combustible material (wax, stearin, paraffin) serving as a kind of reservoir of solid fuel supplied in molten form to the flame with a wick. The ancestors of the candle are lamps; bowls filled with vegetable oil or low-melting fat, with a wick or just a splinter for lifting fuel into the combustion zone. Some peoples used wicks inserted into the raw fat (even the carcass) of animals, birds or fish as primitive lamps. The first wax candles appeared in the Middle Ages. Candles have been very expensive for a long time. To illuminate a large room, hundreds of candles were required, they smoked, blackening the ceilings and walls. Candles have come a long way since their inception. People changed their purpose and today people have other sources of light in their homes. But, nevertheless, today candles symbolize a holiday, help create a romantic atmosphere in the house, calm a person, and are an integral part of the decor of our homes, bringing comfort and coziness to the house with them. A candle can be made from pork or beef tallow, oils, beeswax, whale oil, paraffin, which is obtained from oil. Candles made from paraffin wax are easiest to come across today. We will conduct experiments with them today.

II Updating students' knowledge.

Briefing. Safety regulations

Conversation:

Light a candle. You will see how the paraffin wax near the wick begins to melt, forming a round puddle. What process is taking place here? What happens when a candle burns? After all, the paraffin just melts. But where does the warmth and light come from then?

What happens when a light bulb is on?

Students' answers.

Teacher:

When the wax just melts, there is no heat or light. Most of the wax is burned to form carbon dioxide and water vapor. Because of this, warmth and light appear. And from the heat, part of the paraffin melts, because it is afraid of the hot. When the candle burns out, there will be less paraffin than it was at the beginning. But when an electric light is on, heat and light are also emitted, and the light does not get smaller? The burning of a light bulb is not a chemical but a physical phenomenon. It does not burn by itself, but converts the energy of electricity into light and heat. As soon as you turn off the electricity, the light goes out. And you just have to light a candle, then it burns itself.

And now our task is to look at the candle flame and the candle itself through the eyes of a researcher.

III Study of new material.

Experiment "Construction of a Candle"

WHAT THEY WERE DOING?	WHAT HAVE BEEN OBSERVED?	CONCLUSIONS
1. Considered a paraffin and wax candle. 2. Detached the wick.	The candle consists of a rod and a wick of tightly twisted threads in the center of the post.	The base of the candle is wax or paraffin. The wick is a kind of capillary through which the melt of the candle mass enters the combustion zone. Wicks are woven from cotton threads. Wax candles should have a loosely woven wick of thick fibers; for all other candles, wicks are made from tightly woven threads. This is due to the viscosity of the candle mass in the molten state: for viscous wax, wide capillaries are needed, and readily mobile paraffin, stearin and fats require thinner capillaries, otherwise, due to an excess of combustible material, the candle will smoke heavily.

Experience "Study of the physical and chemical processes occurring during the burning of a candle"

WHAT THEY WERE DOING?	WHAT HAVE BEEN OBSERVED?	CONCLUSIONS
1.Light a candle.	1.Burning a candle. If you bring your palms to the flame, you feel warm.	1. A candle is a source of heat, because the combustion process of gaseous paraffin is exothermic.
2. Studied the sequence of the candle burning process. We observed the phase transformations that occur with the candle.	2. Paraffin begins to melt near the wick and from a solid state turns into a liquid state, forming a round puddle.	2. When a candle burns, phase transformations of paraffin (physical phenomena), an osmotic phenomenon, chemical transformations are observed.
3. Conducted observation of the cotton wick, found out its role in the burning of a candle.	3. The candle does not burn along the entire wick. Liquid paraffin wets the wick, allowing it to burn. The paraffin itself does not burn. The cotton wick stops burning at the level where the liquid paraffin appears.	3. The role of liquid paraffin is to prevent the wick from burning out quickly, to promote its long burning. Liquid paraffin near the fire vaporizes, releasing carbon, the vapor of which supports the combustion. If there is enough air near the flame, it burns clearly. The melted paraffin extinguishes the flame, so the candle does not burn along the entire wick.

Experience “Study of the structure of a candle flame. Detection of combustion products in a flame. Observing flame discontinuities "

WHAT THEY WERE DOING?	WHAT HAVE BEEN OBSERVED?	CONCLUSIONS
1.Light a candle placed in a candlestick. They let her flare up well.	The candle flame has an oblong shape. A different color is observed in different parts of the flame. In the calm flame of a candle, 3 zones are distinguished. The flame has a somewhat elongated appearance; at the top it is brighter than at the bottom, where the middle part is occupied by a wick, and some parts of the flame, due to incomplete combustion, are not as bright as at the top.	The phenomenon of convention, thermal expansion, Archimedes' law for gases, as well as the law of universal gravitation with gravity forces force the flame to acquire a characteristic cone-shaped shape. The ascending air current gives the flame an oblong shape. the flame that we see is stretched out under the influence of this air current to a considerable height.
2. We took a thin long chip, which we hold horizontally and slowly pass it through the widest part of the flame, not allowing it to catch fire and smoke heavily.	A trace left by a flame remains on the chip. There is more soot above its outer edges, more above the middle.	The part of the flame that is directly adjacent to the wick consists of heavy paraffin vapor - it appears to be blue-violet in color. This is the coldest part of the flame. The second, lightest part is created by hot paraffin vapors and coal particles. This is the hottest area. The third, outer layer contains the most oxygen and glows faintly. Its temperature is high enough, but somewhat lower than the temperature of the light part. It is, as it were, cooled by the surrounding air.
3. We took a piece of white thick cardboard, hold it horizontally in our hand, quickly lower it on top of the flame of a burning candle.	Burning flame appears on the top side of the cardboard.	A ring-shaped opaline has formed on the cardboard. the center of the flame is not hot enough to char the cardboard. The flame has different temperature regions.
4. A glass rod was brought into the candle flame.	The candle flame is yellowish orange in color and glows. Soot forms on the surface of the glass rod.	The glowing nature of the flame is due to the degree of oxygen consumption and the completeness of wax combustion, condensation of carbon and the glow of its incandescent particles. Soot indicates incomplete combustion of paraffin and the release of free carbon.
5. The dry test tube was fixed in the holder, turned upside down and held over the flame of an alcohol lamp.	The walls of the test tube are fogged up. Water droplets form on the walls of the tube.	Water is a product of candle combustion.

Experience "Studying the dependence of the height of the candle flame on the length of the wick"

WHAT THEY WERE DOING?	WHAT HAVE BEEN OBSERVED?	CONCLUSIONS
1.Light a candle.	The wick of the candle lights up, the flame of the candle is high.	Liquid paraffin wets the wick, allowing it to burn. The paraffin itself does not burn. The role of liquid paraffin is to prevent the wick from burning out quickly, to promote its long burning. Liquid paraffin near the fire vaporizes, releasing carbon, the vapor of which supports the combustion. If there is enough air near the flame, it burns clearly.
2. Cut off a part of the burnt wick	The size of the flame has changed, it has decreased in size. The flame descends down the wick to molten paraffin and fades. It burns longer at the top. The part of the paraffin closer to the wick melts from the heat.	Drops of liquid paraffin are less attracted to each other than to the wick, and are easily drawn into the smallest gaps between the threads. This property of a substance is called capillarity.

Experience "Proof of burning a candle in oxygen in the air"

WHAT THEY WERE DOING?	WHAT HAVE BEEN OBSERVED?	CONCLUSIONS
1. A burning candle was placed in the middle of the plate (thin, small, attached with plasticine) Dyed water was poured into the plate (to hide the bottom), the candle was covered with a faceted glass.	Water starts to crawl under the glass The candle is gradually extinguished.	The candle burns as long as there is oxygen in the glass. As oxygen is consumed, the candle goes out. Due to the vacuum that has formed there, the water rises up. Combustion is a complex physicochemical process of interaction of components of a combustible substance with oxygen, proceeding at a sufficiently high speed, with the release of heat and light.

Experience “The influence of air on the burning of a candle. Observing the flame of a burning candle "

WHAT THEY WERE DOING?

WHAT HAVE BEEN OBSERVED?

CONCLUSIONS

They brought a lighted candle to the ajar door. 1. Put a candle on the floor. 2. Carefully stood on a stool near the ajar door, hold a lighted candle in the upper part of the door.

1. The flame is deflected towards the room.

2. The flame is deflected towards the corridor.

Warm air above flows out of the room, while below the cold stream is directed inward.

3. They overturned the candle so that the fuel flowed onto the wick.

The candle will go out

The flame did not have time to heat the fuel so that it could burn, as it happens at the top, where the fuel enters the wick in a small amount and is fully exposed to the flame.

Experience "Study of the smoke of an extinguished candle"

Experience "Qualitative reaction for the detection of candle combustion products"

WHAT THEY WERE DOING?	WHAT HAVE BEEN OBSERVED?	CONCLUSIONS
1.Lime water was poured into a glass. The candle stub was planted on a wire so that it would be more convenient to lower it into a glass.		Lime water can be prepared as follows: you need to take some quicklime, shake it in water and strain through absorbent paper. If the solution turns out to be cloudy, you must strain it again so that it is completely transparent.
2. We lit a candle stub and lowered it carefully to the bottom of an empty glass. They took out the cinder, lit it and put it back in the jar.	The candle burns for a while and then goes out. The candle burns out immediately	The glass contains colorless and odorless gas that does not support combustion and prevents the candle from burning. This is carbon dioxide - CO 2..
3. Add lime water to a glass.	The water in the glass becomes cloudy.	When a candle burns, carbon dioxide is formed. Carbon dioxide makes lime water cloudy.

IV Consolidation of the studied material.

Frontal poll:

List the sequence of candle burning processes.

What phase transformations are observed during candle burning?

What is the combustible material of a candle?

What is a cotton wick for?

What phenomenon allows liquid paraffin to rise to a certain height?

Where is the hottest part of the flame?

Why is the candlestick length decreasing?

Why is the candle flame not extinguished, although the combustion produces substances that do not support combustion?

Why does the candle go out when we blow on it?

What conditions are necessary for a longer and better burning of a candle?

How can you extinguish a candle? What properties are these methods based on?

What is a qualitative response to carbon dioxide?

Teacher:

An examination of the structure and burning of a candle convincingly illustrates the complexity of the most trivial everyday objects around us, testifies to how inseparable such sciences as chemistry and physics are. A candle is such an interesting object of study that the topic cannot be considered exhausted.

In conclusion of our lesson, I want to wish you that you, like a candle, radiate light and warmth to those around you, and that you are beautiful, bright, necessary, like the candle flame that we talked about today.

V Homework.

1. Assignment for those wishing to carry out research work at home:

Take for experience any thing that has a zipper. Open and close the zipper several times. Remember your observations. Rub a paraffin candle over the zipper, for example, on a sweatshirt. (Don't forget to ask your mom for permission when you pick up the sweater for the experiment.) Has the zipper movement changed?

Answer the question: "Why do they sometimes rub a candle on the zippers?"

(The substances from which the candlestick is made (stearin, paraffin) are a good lubricant that reduces friction between the links of the fastener.)

2. Assignment for those wishing to carry out research work at home.

Take 3 candles of different composition, made of paraffin, wax, stearin. You can buy candles at the store, or you can make yourself. (Ask Mom or Dad to watch the experience with you.) Wait until dusk, place the candles close to each other and light them. Fill out the table as you observe the burning candles.

References.

1. Faraday M .., History of a candle, M., Science, 1980.

1. Smoking will be observed when there is insufficient oxygen in the combustion atmosphere. I don’t know how to do it. add water vapor.
2. In a large jar, the oxygen did not completely burn out, but some percentage of it remained, so the left candle burned longer than ideally.
Michael,
1. The first question needs an exact solution. The general direction of thought is correct - combustion with a lack of oxygen, but that didn't work out for me. I tried to just cover the jar with a lid, the flame just gradually goes out, and that's it. There is no smoking.
2. I don’t think there will be oxygen in the big jar. The flame causes strong stirring throughout the volume. Hot carbon dioxide rises up - cools down from the can - goes down. Plus, its density is 1.5 times higher than that of air, so it will also go down.
Apparently, some of the carbon dioxide went down from 3 liters. Most likely, the experiment will succeed if the jar is sealed with a piece of plastic lid and turned over before closing it with a cardboard.
P. S.
CO2 = 46
Air = 29
The total difference is 1.5 times
You can light a candle, for example, by the chemical reaction of potassium permanganate with sulfuric acid
KMnO4 + H2SO4 (conc.)
the resulting oxide, when interacting with paraffin, will ignite it
According to the procedure: I think the answers had to be hidden so that the "second" did not see the answers of the "first", so that there were no disputes - the competition was
Essentially: there is nothing else in the head, there is no way to wool the Internet right now ...
Mikhail, it's okay to be open to comments. The first correct answer still counts.
You don't need to scratch the Internet, there is more logic and basic knowledge of physics and chemistry. And, of course, imagine all the nuances of the experiment in your head.
On the second question: - "Why does the left candle burn for so long?"
gas flame is less.
On the first question, there is an assumption, perhaps the candle will smoke when the wick is long, that is, the wick burns and burns oxygen around.
Sergey, I agree. It is very difficult to make a quantitative assessment here. Who said that the flame of both candles burns equally intensely? By eye, it seems to be the same, but maybe one consumes more oxygen than the other. And second - the processes of flame extinction themselves. As a result, it turns out that we can only give a qualitative ("yes, the left candle burns less"), but not a quantitative one.
Andrey August 4, 2010, 06:01
About burning. The candle "consumes" not all oxygen, but very little. I had a need to organize an oxygen-free atmosphere, and I was just thinking of making it a candle, but I read on the "cavemen" forums that if a candle went out in a closed cave, then there was only a couple of percent less oxygen. Well, carbon dioxide is there two or three percent, or what? I do not remember.
Well, besides, there is also such a thing as convection. Carbon dioxide is heavier than air and collects from below, and air from above, thus, is somewhat richer in oxygen. This is what allowed the candle to burn out longer.
And how to make her smoke - offhand and I will not say, you need to play around.
Andrey, did not understand how the thought about convection and the fact that "Carbon dioxide is heavier than air and collects at the bottom, while the air at the top is thus somewhat richer in oxygen."... If there is strong convection from the flame, as I wrote above, then everything inside the can is quickly mixed, and there is no role where what is collected.
Anatoly, you can also bring any object into the middle zone of the flame, where incomplete combustion occurs. Then soot is deposited on the object. This is how glass is smoked. And you can also observe it here:
Here you can clearly see how the rod and the plastic bag got smoked.
I am still waiting for the last correct answer, where the excess oxygen could have come from in the closing jar. Hint: think in the direction of thermal expansion of gases.
(hit because the pressure in the bank began to decrease)
As for the first question, I think there is already an answer. It is necessary to do some kind of manipulation so that incomplete oxidation occurs: it can be, for example, an object brought up by a thread - the vapor of burning paraffin will cool sharply, not having time to completely burn out (this is still a cold object). If I’m not mistaken, it’s like it can happen with the addition of some chemicals to the wick of the candle.
Regarding the second point:
In general, the burning of a candle in this case can be considered as an inertial link of the n-th order. In the simplest case, if the oxygen combustion rate is directly proportional (although it may be proportional to the square, cube ... concentration). In this case, the less oxygen in the can, the slower it burns. In general, VCO2 (t) = K1 * e ^ (- k2 / t). This non-linear equation of carbon dioxide content explains why with "clean" air of 0.5 liters, the candle will burn twice as long as with 2.5 liters - just at first the combustion will be very intense and almost 2 liters of air are used in the first 10 seconds and, as in the second case, only 0.5 liters will remain, which will burn out for another 30 seconds.
esfir January 2, 2014, 06:37
Quote: "Wax candles should have a loosely woven wick of thick fibers, for all other candles, wicks are made of tightly woven threads. This is due to the viscosity of the candle mass in the molten state: for viscous wax, wide capillaries are needed, and easily mobile paraffin, stearin and fats require thinner capillaries, otherwise the candle will smoke heavily due to the excess of combustible material. "
Option: put a piece of loose rope in the paraffin melted near the wick.
I noticed that he starts smoking when the wick is slightly moistened, i.e. the heating temperature of the wick itself is below average when burning dry fillets. The flame itself, naturally, has a normal temperature, because oxygen burns, and the wick only supports combustion. You have to spit on your finger, run it over the wick and set it on fire - it will smoke
All this is very interesting. But, "great minds" can you answer another question? As long as the candle is burning, it does not smell. And that's okay, because clean water and carbon dioxide are odorless. But! As soon as you extinguish the candle, you will get a strong unpleasant smell! Incomplete combustion produces the same water, pure carbon C and CO instead of CO2, but C and CO are also odorless. Then what smells so bad when we put out a candle?
5 January 2017, 06:15
Pavel, as I understand it, it smells like products of incomplete combustion of paraffin. That is, at the moment of extinguishing the candle, there must be a fairly large range of all molecular compounds.

Option 1

Instructions for students

The test consists of parts A, B and C. It takes 40 minutes to complete it. It is recommended to complete the tasks in order. If the task cannot be completed right away, go to the next one. If time remains, return to missed assignments.

Part A

A1. In which series are simple non-metal substances:

1) chlorine, nickel, silver 3) iron, phosphorus, mercury

2) diamond, sulfur, calcium 4) oxygen, ozone, nitrogen

A2. The chemical element of the 3rd period of the V group of the periodic system of D.I. Mendeleev corresponds to the diagram of the distribution of electrons over the layers:

1) 2,8,5 2) 2,3 3) 2,8,3 4) 2,5

A3. For elements of the carbon subgroup, with an increase in atomic number, it decreases:

1) atomic radius 3) number of valence electrons in atoms

2) the charge of the nucleus of an atom 4) electronegativity

A4. Strongest chemical bond in a molecule

1) F 2 2) Cl 2 3) O 2 4) N 2

A5. The interaction of ammonia with hydrogen chloride refers to the reactions:

1) decomposition 2) compound 3) substitution 4) exchange

A6. Abbreviated ionic reaction equation Ag + + Cl -  AgCl

corresponds to the interaction between solutions:

1) silver carbonate and hydrochloric acid

2) silver nitrate and sulfuric acid

3) silver nitrate and hydrochloric acid

4) silver sulfate and nitric acid

A7. A burning candle goes out in a jar sealed with a cork, because:

1) there is not enough oxygen 3) the nitrogen content rises

2) the temperature rises 4) water vapor is formed, extinguishing the flame

A8. With the help of a solution of sulfuric acid, you can carry out the transformations:

1) copper  copper (II) sulfate 3) sodium carbonate  carbon (IV) oxide

2) carbon  carbon (IV) oxide 4) silver chloride  hydrogen chloride

Part B.

IN 1. Non-metallic properties in the series of elements Si  P  S  Cl from left to right:

1) do not change 3) weaken

2) increase 4) change periodically

IN 2. The displacement of the equilibrium of the N 2 + 3H 2 2 NH 3 + Q system towards the reaction product will occur in the case of:

A) increasing the concentration of ammonia

B) using a catalyst

B) decrease in pressure

D) reducing the concentration of ammonia

AT 3. What volume (n.s.) of hydrogen chloride can be obtained from 2 mol of chlorine?

Part C.

C1. Find the mass of sulfuric acid required to neutralize 200 g of 20% sodium hydroxide solution.

Examination in inorganic chemistry, topic "Non-metals", grade 9

Option 2

Instructions for students

The test consists of parts A, B and C. It takes 40 minutes to complete it. It is recommended to complete the tasks in order. If the task cannot be completed immediately, skip to the next one. If there is time left, go back to the missed tasks.

Part A.

For each task in part A, several answers are given, of which only one is correct. Choose the answer that is correct in your opinion.

A1. Oxygen as a simple substance is spoken of in the sentence:

1) plants, animals and humans breathe oxygen

2) oxygen is part of water

3) oxides consist of two elements, one of which is oxygen

4) oxygen is part of the chemical compounds that make up living

A2. In a phosphorus atom, the total number of electrons and the number of electron layers, respectively

are equal: 1) 31 and 4 2) 15 and 5 3) 15 and 3 4) 31 and 5

A3. The sum of protons and neutrons in a carbon atom is equal:

1) 14 2) 12 3) 15 4) 13

A4. Covalent polar chemical bond is characteristic for:

1) KCl 2) HBr 3) P 4 4) CaCl 2

A5. The reaction, the equation of which is 3N 2 + H 2 2NH 3 + Q, refers to the reactions:

1) reversible, exothermic 3) reversible, endothermic

2) irreversible, exothermic 4) irreversible, endothermic

A6. In order to prove that there is a solution of carbonic acid in the test tube,

it is necessary to use: 1) hydrochloric acid 3) a smoldering splinter

2) ammonia solution 4) sodium hydroxide solution

A7. A sign of the reaction between hydrochloric acid and zinc is:

1) odor 3) gas evolution

2) sediment formation 4) solution color change

A8. The reduced ionic equation Ba 2+ + SO 4 2-  BaSO 4 corresponds

Interaction between: 1) barium phosphate and sulfuric acid solution

2) solutions of sodium sulfate and barium nitrate

3) solutions of barium hydroxide and sulfuric acid

4) barium carbonate and sulfuric acid solution

Part B.

IN 1. With a decrease in the serial number in the A (main) subgroups of the periodic system of D.I. Mendeleev, the non-metallic properties of chemical elements:

1) do not change 3) change periodically

2) increase 4) weaken

The answer to task B2 is a sequence of letters. Write down the selected letters in alphabetical order.

IN 2. Which of the following conditions not will affect the displacement of the equilibrium in the system

H 2 + Cl 2 2HCl - Q: A) lowering the temperature

B) temperature rise

C) the introduction of the catalyst

D) lowering the concentration of HCl

D) lowering pressure

AT 3. What volume of gas (n.u.) will be released during the complete combustion of 600 g of coal?

Part C.

C1. When treating 300 g of wood ash with an excess of hydrochloric acid, 44.8 liters (NU) of carbon dioxide were obtained. What is the mass fraction (%) of potassium carbonate in the original ash sample?

Work instructions

40 minutes are allotted for the performance of control work in chemistry on the topic "Non-metals". The work consists of three parts (A, B and C) and includes 12 tasks.

Part A contains 8 tasks (A1 –A8). For each task, 4 possible answers are given, of which only one is correct.

Part B contains 3 tasks (B1 - B3). To one of them (B1) 4 possible answers are given, of which only one is correct. For task B2, you need to write down the answer in the form of a sequence of letters, and for task B3 - in the form of a number.

Part C contains one of the most difficult tasks to which a complete (detailed) answer should be given.

The approximate time for completing the tasks of part A is 15 minutes, part B - 15 minutes, part C - 10 minutes.

Completion of tasks of various complexity is estimated at 1, 2 or 3 points. The points received for all completed tasks are summed up.

Correct performance of each task of part A1 –A8 and task B1, i.e. assignments with a choice of answer, is evaluated by one point.

The maximum mark for correct performance of tasks (B2) with a short answer is two points. An assignment with a short answer for correspondence or multiple choice is considered completed correctly if the student chooses two correct ones out of the five proposed answers. In other cases: one correct is selected; more than two answers were chosen, among which one is correct; among the two selected answers, one is incorrect, the task is evaluated by one point. If there are no correct answers among the selected answers, the task is considered unfulfilled. The student receives 0 points. Task (B3) with a short answer in the form of a calculated problem is considered completed correctly if the student's answer indicates the correct sequence of numbers (number).

The task with a detailed answer involves checking the assimilation of three elements of the content. The presence in the answer of each of these elements is evaluated by one point (3-0 points).

The assessment of work on a five-point scale is determined on the basis of the total number of points received for completing tasks:

"5" - 13-15 points

"4" - 10-12 points

"3" - 7 - 9 points

"2" - 1 - 6 points

Answers and solutions

No. A1 A2 A3 A4 A5 A6 A7 A8 B1 B2 B3 C1

1 4 1 4 4 2 3 1 3 2 VG 89.6L 49g

2 1 3 2 2 1 1 3 2 2 HP 1120L 92%

Option 1 (C1)

1) Compiled the reaction equation H 2 SO 4 + 2NaOH = Na 2 SO 4 + 2H 2 O

2) Calculated the mass of sodium hydroxide

m (NaOH) = 200 * 20/100 = 40 (g)

3) Found the mass of sulfuric acid m (H 2 SO 4) = 98 * 40/80 = 49 (g)

Option 2 (C1)

1) Compiled the reaction equation K 2 CO 3 + 2HCl = 2KCl + CO 2 + H 2 O

2) Calculated mass of potassium carbonate

m (K 2 CO 3) = 138 * 44.8 / 22.4 = 276 (g)

3) The mass fraction of potassium carbonate in the ash sample was determined

w (K 2 CO 3) = 276 * 100/300 = 92 (%)

Compiled by the teacher of chemistry MOU SOSH №58

Tikhomirova I.P.

Approximate plan of test work on the topic "Non-metals" for grade 9

Number Number Checked elements of content Task type Grade

Block tasks in points

Part A (I)

1 I Simple and complex substances VO 1

2 I Periodic law and periodic system

chemical elements D.I. Mendeleev. Groups

and periods of the periodic system. IN 1

3 I The structure of the atom. The structure of electronic shells

atoms of elements No. 1-No. 20 p.s.c.e. IN 1

4 I Chemical bond: ionic, metallic,

covalent (polar, non-polar) VO 1

5 I Classification of chemical reactions by

various signs. Chemical equations VO 1

6 I Properties of ions. Qualitative reactions to anions. IN 1

7 I Chemical properties of simple substances: metals and

non-metals VO 1

8 I The relationship of inorganic substances of various

classes BO 1

Part B (II)

1 II Regularities of changes in the properties of elements and their

compounds in connection with the situation in the P.S.H.E. IN 1

2 II Reversible and irreversible reactions. Chemical

equilibrium. KO 2

3 II Calculation of mass, volume or quantity of one

of the substances participating in the reaction. KO 1

Part C (III)

1 III Calculations using the equations of chemical reactions with

using solutions with a certain mass

fractions of a solute. Finding the mass

pure substance using the concept of "impurity" PO 3

Total points 15

Designations of the types of tasks: VO- choice of answer

KO- short answer

RO - detailed answer

Statistical information on the results of the completion of a / work on __________ (consolidated)

School number ______ class ______ Full name. teachers __________________________________

Date of completion of work _________________ Lesson number __________________________

Implemented programs and textbooks on the subject ____________________________________________________________________________

1. Results of the work:

	Number of students completed work		including those who completed
	Number of students completed work

2. The quality of ZUN (the number of students who completed work on the "4-5" ______ people ._____%

3. The level of training (number of students who completed work at "3,4,5" ____ people .____%

4. The level of formation of the ZUN.

as a whole on a / r

including by levels of knowledge

coped

fully

allowed

coped

started

5. Comparison table(data to / r with data for ________________________)

* in total ______________ people wrote the work .__________%

* confirmed the mark by _____________ people __________%

* received a mark below __________ people. __________%

* received a mark above __________ people. __________%

6. Of the total number of absentees, they have a grade for the year:

Methodical instructions

... on fulfillment control works By course " Chemistry»Each student performs one control work ... themes... oxidative activity non-metals in the period ... × 10-8 0.05 Table 9 Main classes inorganic Substances Substances Classification of substances P r ...

Test work in chemistry for students of grade 11 of a secondary school explanatory note

Explanatory note

Unified State Exam on chemistry... She tests the knowledge of students on themes"Structure of matter" and "Basic classes inorganic substances ". Control Work ... -non-metals: hydrogen, halogens, oxygen, sulfur, nitrogen, phosphorus, carbon, silicon. Control Work ...

Methodical instructions and control tasks in chemistry. Yekaterinburg: go vpo "Ros state prof ped university" works on subjects of the curriculum. Russian language. MONTH WEEK CLASS THEME... A KR No. 3 " Nonmetals". 10A KR No. 2 "... Inorganic chemistry". 11.05 - 15.05 8 А, B КР № 5 "Redox reactions". 9 А КР № 5 "Final control Work ...

Option 1

Instructions for students

Part A

A1. In which series are simple non-metal substances:

1) chlorine, nickel, silver 3) iron, phosphorus, mercury

2) diamond, sulfur, calcium 4) oxygen, ozone, nitrogen

A2. The chemical element of the 3rd period of the V group of the periodic system of D.I. Mendeleev corresponds to the diagram of the distribution of electrons over the layers:

1) 2,8,5 2) 2,3 3) 2,8,3 4) 2,5

A3. For elements of the carbon subgroup, with an increase in atomic number, it decreases:

1) atomic radius 3) number of valence electrons in atoms

2) the charge of the nucleus of an atom 4) electronegativity

A4. Strongest chemical bond in a molecule

1) F2 2) Cl2 3) O2 4) N2

A5. The interaction of ammonia with hydrogen chloride refers to the reactions:

1) decomposition 2) compound 3) substitution 4) exchange

A6. Abbreviated ionic reaction equation Ag + + Cl-◊ AgCl

corresponds to the interaction between solutions:

1) silver carbonate and hydrochloric acid

2) silver nitrate and sulfuric acid

3) silver nitrate and hydrochloric acid

4) silver sulfate and nitric acid

A7. A burning candle goes out in a jar sealed with a cork, because:

1) there is not enough oxygen 3) the nitrogen content rises

2) the temperature rises 4) water vapor is formed, extinguishing the flame

A8. With the help of a solution of sulfuric acid, you can carry out the transformations:

1) copper ◊ copper (II) sulfate 3) sodium carbonate◊ carbon monoxide (IV)

2) carbon ◊ carbon monoxide (IV) 4) silver chloride◊ hydrogen chloride

Part B.

IN 1. Non-metallic properties in the series of elements Si - P - S - Cl from left to right:

1) do not change 3) weaken

2) increase 4) change periodically

IN 2. The displacement of the equilibrium of the N2 + 3H2 2 NH3 + Q system towards the reaction product will occur in the case of:

A) increasing the concentration of ammonia

B) using a catalyst

B) decrease in pressure

D) reducing the concentration of ammonia

AT 3. What volume (n.s.) of hydrogen chloride can be obtained from 2 mol of chlorine?

Part C.

C1. Find the mass of sulfuric acid required to neutralize 200 g of 20% sodium hydroxide solution.

C2.

Examination in inorganic chemistry, topic "Non-metals", grade 9

Option 2

Instructions for students

Part A.

For each task in part A, several answers are given, of which only one is correct. Choose the answer that is correct in your opinion.

A1. Oxygen as a simple substance is spoken of in the sentence:

1) plants, animals and humans breathe oxygen

2) oxygen is part of water

3) oxides consist of two elements, one of which is oxygen

4) oxygen is part of the chemical compounds that make up living

Cell

A2. In a phosphorus atom, the total number of electrons and the number of electron layers, respectively

Equals: 1) 31 and 4 2) 15 and 5 3) 15 and 3 4) 31 and 5

A3. The sum of protons and neutrons in a carbon atom is equal:

1) 14 2) 12 3) 15 4) 13

A4. Covalent polar chemical bond is characteristic for:

1) KCl 2) HBr 3) P4 4) CaCl2

A5. The reaction, the equation of which is 3N2 + H2 2NH3 + Q, refers to the reactions:

1) reversible, exothermic 3) reversible, endothermic

2) irreversible, exothermic 4) irreversible, endothermic

A6. In order to prove that there is a solution of carbonic acid in the test tube,

It is necessary to use: 1) hydrochloric acid 3) a smoldering splinter

2) ammonia solution 4) sodium hydroxide solution

A7. A sign of the reaction between hydrochloric acid and zinc is:

1) odor 3) gas evolution

2) sediment formation 4) solution color change

A8. Abbreviated ionic equation Ba2 + + SO42-◊ BaSO4 corresponds

Interaction between: 1) barium phosphate and sulfuric acid solution

2) solutions of sodium sulfate and barium nitrate

3) solutions of barium hydroxide and sulfuric acid

4) barium carbonate and sulfuric acid solution

Part B.

IN 1. With a decrease in the serial number in the A (main) subgroups of the periodic system of D.I. Mendeleev, the non-metallic properties of chemical elements:

1) do not change 3) change periodically

2) increase 4) weaken

The answer to task B2 is a sequence of letters. Write down the selected letters in alphabetical order.

IN 2. Which of the following conditions will not affect the displacement of the equilibrium in the system

H2 + Cl2 2HCl - Q: A) lowering the temperature

B) temperature rise

C) the introduction of the catalyst

D) lowering the concentration of HCl

D) lowering pressure

AT 3. What volume of gas (n.u.) will be released during the complete combustion of 600 g of coal?

Part C.

C1. When treating 300 g of wood ash with an excess of hydrochloric acid, 44.8 liters (NU) of carbon dioxide were obtained. What is the mass fraction (%) of potassium carbonate in the original ash sample?

Work instructions