Almost every resident of our country found a variety of pests in his home. But the most common question that occurs even in clean housewives is how to find mole and its larvae. After all, the studies of housing gray butterflies are chosen only at night. It is even more difficult to find the laying of eggs and larvae, as they are in secluded places, the existence of which you need to know. Before you begin to combat insects, you need to get acquainted with the paths of penetration and spread of insects.

Before finding the place of dislocation of moth, it is necessary to determine its species affiliation. After all, food, wrames and grain species appear in the house. Groceries feed on food variety insects. They consume flour and spices, grain and sugar, dry foods and fruits. Set the presence of an insect is easy. The larva in the course of eating the croup forms a cocoon of silk. From the grain or flour of the worm make peculiar lumps that are used for pounding. Since food moths are poorly developed wings, it almost does not move throughout the house. The main path of its penetration is acquired cereals or dried fruits. In the apartment there may be a wrapping mole. To lay eggs, this type of pest uses fur things or wool products. It is necessary to search for her larvae.

Food butterfly detection

Worms prefer solid and natural nutrition. They consume patches, cereals, vegetation, as well as nuts and dried fruits. Imago does not consume nutrientsSince their oral apparatus is poorly developed. The lifespan of adult moths in the house ranges from 7 to 21 days. This time is enough, so that the insect has formed several masonry.

Find the pray nest is easy. To do this, review the cereals, fur products and vegetation. IMAGO Eggs in a preformed nest. Over time, worms and dolls appear. Characteristic signs The appearance of gray butterflies:

• Pautinc.
• Lumps.
• Fortune in clothing.
• Vault at the bottom of the cabinet.

To detect pests, you need to revise products and periodically check the wardrobe.

Causes of appearance

Before finding food or hard mole In the apartment, you need to familiarize yourself with the main reasons for its appearance. To infect residential premises, only one fertilized individual will be required. Gray Butterfly chooses those houses and apartments in which there is suitable conditions. To the main sources of moth appearances in the apartment:

• Penetration through holes in building materials and doorways.
• Penetration through windows that are not covered with a mosquito net.
• Purchase of clothes or food products that were infected with larvae.
• Penetration ventilation holesas well as air ducts.

To exclude a similar outcome, you need acquired cereals, things and other items to revise. By installing where the pest moves, it is easier to cope with them.

Signs of presence

Determine what mole started, easy. After all, in secluded places insect leaves eggs. But to find the pest brood problematic, since eggs differ in small sizes. Inspecting kitchen headsets and wardrobes, you should pay attention to the presence of a pile and cobwebs. Indeed, in the process of eating a cereal or natural pile of the larvae form cocoons from silk.

If the insect in the house is one, then find a flying mole housewives can not. With excessive infection of the premises, gray butterflies are chosen out and are engaged in searching for secluded places.

How to protect housing

If mole starts, then the damage can be quite serious. After all, cereals in which the insect postponed eggs, it is impossible to consume. To prevent housing infection, as well as to get rid of insects, you should use folk and chemicals.

Folk remedies

Installing where a gray butterfly or larva lives, you need:

1. Prepare a solution including vinegar or strawberry and laundry soap. This solution is used for cleaning. kitchen headset and other surfaces. It also happens that they carry out additional processing.
2. To scare off pests bay leaf, garlic, lavender or citrus crusts. Since over time, the fragrance evaporates, make a replacement of crusts or laurels.
3. You can scare insects with cedar twigs and pieces of wood.
4. For the protection of wardrobes fit essential oilsas well as extracts. They are used to apply on cotton disks or pieces of fabric.

Chemicals

Manufacturers supply a variety of drugs and devices that are eliminated from the wrapping or food moth. Among the extensive range allocate:

• Aerosol preparations. They are suitable for treating objects infected with larvae and pupae, as well as pest habitats. Rapator aerosols are used to protect, as well as a clean house.

Purpose: To acquaint students with the concepts of "Number of substance", "Molar Mass" to give an idea of \u200b\u200bconstant Avogadro. Show the relationship of the amount of substance, the number of particles and the constant Avogadro, as well as the relationship of the molar mass, mass and amount of the substance. Teach to make calculations.

Type of lesson:lesson studying and primary consolidation of new knowledge.

During the classes

I. Organizational moment

II. Verification of d / s on the topic: "Types of chemical reactions"

III. Studying a new material

1. The amount of substance is mole

Substances react into strictly certain ratios. For example, to obtain a substance of water, you need to take so much hydrogen and oxygen so that every two hydrogen molecules accounted for one oxygen molecule:

2N 2 + O 2 \u003d 2N 2

To obtain a substance of iron sulphide, you need to take so much iron and sulfur so that each atom of iron accounted for one sulfur atom.

To obtain a substance of phosphorus oxide, you need to take so many molecules of phosphorus and oxygen so that four phosphorus molecules accounted for five oxygen molecules.

It is impossible to determine the number of atoms, molecules and other particles in practice - they are too small and are not visible to the naked eye. To determine the number of structural units (atoms, molecules) in chemistry, a special amount is used - number of substance ( v - NU). Unit amount of substance is mole.

• Mol is the amount of substance that contains so many structural particles (atoms, molecules), how many atoms are contained in 12 g of carbon.

It is experimentally established that 12 g of carbon contains 6 · 10 23 atoms. So one moth of any substance, regardless of its aggregate state, contains the same number of particles - 6 · 10 23.

• 1 mole oxygen (O 2) contains 6 · 10 23 molecules.
• 1 mol of hydrogen (H 2) contains 6 · 10 23 molecules.
• 1 mol of water (H 2 O) contains 6 · 10 23 molecules.
• 1 mole of iron (FE) contains 6 · 10 23 molecules.

The task: Using the information received, respond to questions:

a) how many oxygen atoms are contained in 1 oxygen mole?

- 6 · 10 23 · 2 \u003d 12 · 10 23 atoms.

b) how many hydrogen and oxygen atoms are contained in 1 mall of water (H 2 O)?

- 6 · 10 23 · 2 \u003d 12 · 10 23 hydrogen atoms and 6 · 10 23 oxygen atoms.

Number 6 · 10 23 named constant avogadro In honor of the Italian 19th century scientist and is denoted by NA. Units of measurement atoms / mole or molecules / mole.

2. Solving tasks to find the amount of substance

Often you need to know how many particles of the substance are contained in a certain amount of substance. Or find the amount of substance at a well-known number of molecules. These calculations can be made by the formula:

where n is the number of molecules, NA is constant Avogadro, v. - Number of substance. From this formula, you can express the amount of substance.

Task 1. How many atoms contain in 2 sulfur prayers?

N \u003d 2 · 6 · 10 23 \u003d 12 · 10 23 atoms.

Task 2. How many atoms are contained in 0.5 iron chairs?

N \u003d 0.5 · 6 · 10 23 \u003d 3 · 10 23 atoms.

Task 3. How many molecules are contained in 5 moles of carbon dioxide?

N \u003d 5 · 6 · 10 23 \u003d 30 · 10 23 molecules.

Task 4. What amount of substance is 12 · 10 23 molecules of this substance?

v \u003d.12 · 10 23/6 · 10 23 \u003d 2 mol.

Task 5. What amount of substance is 0.6 · 10 23 molecules of this substance?

v \u003d.0.6 · 10 23/6 · 10 23 \u003d 0.1 mol.

Task 6. What amount of substance is 3 · 10 23 molecules of this substance?

v \u003d.3 · 10 23/6 · 10 23 \u003d 0.5 mol.

3. Molar mass

For chemical reactions It is necessary to take into account the amount of substance in the moles.

Q: But how in practice, measure 2, or 2.5 mol substances? Which units are best to measure the mass of substances?

For convenience in chemistry use molar mass.

The molar mass is the mass of one praying substance.

It is indicated - M. is measured in g / mol.

The molar mass is equal to the ratio of the mass of the substance to the corresponding number of substance.

Molar weight - the magnitude is constant. The numerical value of the molar mass corresponds to the value of the relative atomic or relative molecular weight.

Q: How can I find the values \u200b\u200bof a relative atomic or relative molecular weight?

Mr (s) \u003d 32; M (s) \u003d 32 g / mol - What corresponds to 1 praying sulfur

Mr (H 2 O) \u003d 18; M (H 2 O) \u003d 18 g / mol - which corresponds to 1 praying water.

4. Solving tasks to find the mass of matter

Task 7. Determine the mass of 0.5 mol iron.

Task 8. Determine the mass of 0.25 mole of copper

Task 9. Determine Mass 2 Mol Carbon Dioxide (CO 2)

Task 10.How many moles of copper oxide - Cuo make up 160 g of copper oxide?

v \u003d.160/80 \u003d 8 mole

Task 11.How many moles of water correspond to 30 g of water

v \u003d.30/18 \u003d 1.66 mol

Task 12.How many moles of magnesium correspond to its 40 grams?

v \u003d.40/24 \u003d 1.66 mole

IV. Fixing

Frontal survey:

1. What is the amount of substance?
2. What is 1 mol of any substance?
3. What is a molar mass?
4. Is the concepts of "mole molecules" and "mole atoms"?
5. Explain on the example of the ammonia molecule NN3.
6. Why do you need to know the formulas when solving problems?

Tasks:

1. How many molecules are contained in 180 grams of water?
2. How many molecules is 80 g of carbon dioxide?

V. Homework

Examine the text of the paragraph, make up two tasks: to find the amount of substance; To find the mass of the substance.

Literature:

1. Gara N.N. Chemistry. Lessons in grade 8: manual for teacher. _ M.: Enlightenment, 2009.
2. RUDZITES G.E., Feldman F.G. Chemistry. Grade 8: Textbook for general educational institutions - M.: Enlightenment, 2009.

The concept of mole is used to measure chemical substances. Find out the features of this value, we give examples of settlement tasks with its participation, we define the importance of this term.

Definition

Mole in chemistry is a computation unit. It is the amount of a certain substance in which there are so many structural units (atoms, molecules), as contained in 12 grams of carbon atom.

Number of Avogadro

The amount of substance is associated with the Avogadro number, which is 6 * 10 ^ 23 1 / mol. For substances of the molecular structure, it is believed that one mole includes exactly the number of Avogadro. If you need to calculate the number of molecules contained in 2 moles of water, then you must multiply 6 * 10 ^ 23 to 2, we get 12 * 10 ^ 23 pieces. Let's look at what role mole plays in chemistry.

Number of substances

The substance that consists of atoms contains the number of Avogadro. For example, for the sodium atom is 6 * 10 * 23 1 / mol. What is his designation? Mole in chemistry designate greek letter "NU" or Latin "N". For mathematical computing associated with the amount of substance, the mathematical formula is used:

n \u003d N / N (A), where n is the amount of substance, N (A) is the number of Avogadro, N is the number of structural particles of the substance.

If necessary, you can calculate the number of atoms (molecules):

The actual mass of praying is called molar. If the amount of substance is determined in the moles, the magnitude of the molar mass has a unit of measuring g / mol. In numerical expression, it corresponds to the value of the relative molecular weight, which can be determined by summing up the relative atomic masses of individual elements.

For example, in order to determine the molar mass of the carbon dioxide molecule, the following calculations must be carried out:

M (CO2) \u003d Ar (C) + 2AR (O) \u003d 12 + 2 * 16 \u003d 44

When calculating the molar mass of sodium oxide, we get:

M (Na2O) \u003d 2 * Ar (Na) + Ar (O) \u003d 2 * 23 + 16 \u003d 62

In determining the molar mass of sulfuric acid, we summarize the two relative atomic weights of hydrogen with one atomic mass of sulfur and four relative atomic masses of oxygen. Their values \u200b\u200bcan always be found in periodic table Mendeleeva. As a result, we get 98.

Mole in chemistry allows a variety of calculations associated with chemical equations. All typical estimated tasks in inorganic I. organic Chemistrywhich suggest the finding of the mass and volume of substances, are solved exactly through moths.

Examples of settlement tasks

The molecular formula of any substance indicates the number of moles of each element included in its composition. For example, one mole of phosphoric acid contains three praying of hydrogen atoms, one mole of phosphorus atoms and four praying oxygen atoms. Everything is simple enough. Mole in chemistry is a transition from microworld of molecules and atoms into a macro with kilograms and grams.

Task 1. Determine the number of water molecules contained in 16.5 moles.

To solve, use the relationship between the Avogadro number (the amount of substance). We get:

16.5 * 6,022 * 1023 \u003d 9.9 * 1024 molecules.

Task 2. Calculate the number of molecules contained in 5 g of carbon dioxide.

First, it is necessary to calculate the molar mass this substance, Using her bond with relative molecular weight. We get:

N \u003d 5/44 * 6,023 * 1023 \u003d 6.8 * 1023 molecules.

Algorithm of tasks for chemical equation

When calculating the mass or reaction products, the equation use a specific algorithm of actions. First, determine which of the source substances is shortened. For this, they find their number in moles. Further make up the equation of the process, be sure to arrange stereochemical coefficients. Above the substances are recorded, the source data is recorded, the amount of substance taken in the moles (by the coefficient) is indicated under them. If necessary, translate units of measurement using formulas. Then constitute the proportion and solve it with a mathematical manner.

If a more complex task is proposed, then pre-calculate the mass of the pure substance, removing the impurities, then begin to define its quantity (in miles). No problem in chemistry associated with the reaction equation is not solved without such a magnitude as mole. In addition, using this term, it is easily possible to determine the number of molecules or atoms, using for such calculations with a constant number of Avogadro. Estimated tasks are included in test questions for chemistry for graduates of the main and secondary school.

Homemade mole is a bad neighbor for a person. Of course, it does not bite the skin, but spoils things and products. And when the brown butterflies suddenly begin to fly around the apartment, it is better to immediately score alarm. Where does mole come from in the apartment? It is worth finding out this issue more to be fully armed against a flying insect.

Mole - Types of Butterflies

1. Fur coat. The butterfly of a yellowish color in size up to 1.6 cm harm does not cause a person, because nothing eats. The main goal is to put several eggs of eggs, of which there are voracious larvae. Externally, they resemble worms, have a white translucent color. Worms eat fur coats, hats, collars, tear down in them. In a matter of days, fur turns into a frazzle.

1. Handling. Butterfly size - up to 2 cm, its wings are yellow, the base is purple. Caterpillars are like the same as a fur moth, but settle in the folds of various fabrics, clothes with wool. Butterfly eggs puts right on inner side Fabrics, and, after removing the caterpillars, they immediately begin to eat.

1. Furniture. In the house she begins to postpone the eggs on the upholstery of furniture, as well as in the creams of wood. Caterpillars eating upholstery, then go to the tree. Small butterfly, up to a centimeter with wings, light yellow with brown wing bases.

1. Carpet. The larvae of this butterfly eat carpets, and fur, and even leather products - bags, boots. This mol almost does not respond to standard means - camphor and naphthalene - Therefore, it is sometimes difficult to remove it.

ATTENTION: Food mole is an unprepared person not distinguish between the hardening, but the difference between them is big. This species of butterflies lays eggs directly to food - nuts, cereals, flour, and the larvae eagerly eat them.

Where does the mole of the Hardware come from?

What makes mole in the apartment, it is worth knowing everything, because sometimes even the most accurate, stroking and cleaned things are infected with this attack. Butterfly or eggs can get into the house different ways. If a person suddenly has a furniture mole, it probably happened after buying furniture - sometimes even new.

Where does the kitchen mole appear in the apartment? If the mole is noticed in the kitchen, it most likely got there in the hunt for food products:

• Big and Flour
• Dried fruit
• Nuts
• Spices
• Animal feeds

The food mole attracted by the smell of such food can penetrate the housing from the neighbors, from the entrance. But in most cases, its eggs are already available in food, especially when they are sold for weight. Important reasons for food infection in warehouses - dampness, poor ventilation, disruption of packaging tightness.

Attention: Food mole, more precisely, her caterpillars, very lively. In the cocoon they live even in adverse conditions For a very long time, until they fall into a more suitable Wednesday. In warm, they are withdrawn and eat everything they can eat.

How to prevent the appearance of moths?

Preventive measures that will prevent the appearance of non-crushed tenants are easy. Pouring old things to the house, they need to be properly disinfected - to wash, clean. Special attention to payments to the nonsense furniture - chairs, chairs, sofas, where butterflies and their larvae dwell most often. Large products are recommended to care thoroughly or hold under the straight sunny rays - Insects are dying in such conditions.

Other measures for the prevention of infection with Molia:

1. Use special aerosols before laying clothes for storage.
2. More often to air the wardrobe and cabinets, sneak up the underwear and blankets.
3. Mole does not tolerate lavender aroma, orange, lemon, wormwood, so you can put in the cabinets the corresponding sachets or drop on a cotton disk a bit of essential oil.

1. It is good to inspect all the things brought from the store, especially from wool or fur.
2. Small woolen things can be periodically dried on the battery, large - to carry out on the frost, because the mole does not make both kinds of temperature change.

In the kitchen, all products need to be kept in containers whose covers are densely fitted. Spoiled flour and cereals with worms should be left immediately.

Kitchen headset cabinets need to wash regularly, wipe. They can decompose the lavender to scare insects. If the pests still penetrated the house, they will have to break up to spoiled products and things without pity, and after applying means to combat them (insecticides).

Tips to help get rid of moths:

In chemistry is widely used by the concept " mole" This is such a number substances, which contains approximately 6.02214 * 10 ^ 23 of its elementary particles - molecules, ions or atoms. To facilitate the calculations, this is a huge number called the Nogadro number, often rounded to 6.022 * 10 ^ 23. Mol is measured in grams.

Instruction

To find mole substances, you need to remember very simple rule: the mass of one praying of any substances Numerically equal to its molecular weight, only expressed in other values. And how is the molecular weight determined? With the help of the Mendeleev table, you will learn the atomic mass of each element in the molecule substances. Next, you need to add atomic masses, taking into account the index of each element and the answer will turn out.

For example, widely used in agriculture Fertilizer, ammonium nitrate (or different ammonium nitric acid). The formula of this substances NH4NO3. How to determine what is equal to his mole? First of all, write down the empirical (that is, the general) formula substances: N2H4O3.

Consider its molecular weight, taking into account the index of each element: 12 * 2 + 1 * 4 + 16 * 3 \u003d 76 AE.m. (atomic units of mass). Consequently, its molar mass (that is, the mass of one pray) is also 76, only its dimension: gram / mole. Answer: one mole Ammonium nitrate weighs 76 grams.

Suppose you are given such a task. It is known that the mass of 179.2 liters of some gas is 352 grams. It is necessary to determine how much one weighs mole This gas. It is known that under normal conditions one mole Any gas or mixture of gases occupies a volume of approximately 22.4 liters. And you have 179.2 liters. Calculate: 179.2 / 22.4 \u003d 8. Consequently, this volume contains 8 moles of gas.

By dividing the problem known under the conditions of the problem by the number of moles, get: 352/8 \u003d 44. Consequently, one mole This gas weighs 44 grams are carbon dioxide, CO2.

If there is some amount of gas mass, concluded in volume V at a given temperature T and pressure P. It is required to determine its molar mass (that is, to find what is equal to its mole). Solve the task will help you the universal Mendeleev-Klapairone equation: PV \u003d MRT / M, where M is the very molar mass, which we need to determine, and R is a universal gas constant, equal to 8.31. Converting the equation, get: M \u003d MRT / PV. Substituting in the formula of famous values, you will find what is equal mole Gas.

Various formulas will help to find the amount of substance, the unit of measurement of which is mole. Also, the amount of substance can be found in the reaction equation given in the task.

Instruction

Having a mass and name of the substance without difficulty can find the amount of substance: n \u003d m / m, where n is the amount of substance ( mole), m - mass of substance (g), m - molar mass of substance (g / mole). For example, the mass of sodium chloride is 11.7 g, to find the amount of substance. To substitute the necessary values \u200b\u200bin the formula, you need to find the molar mass of sodium chloride: M (NaCl) \u003d 23 + 35.5 \u003d 58.5 g / mole. We substitute: n (naCl) \u003d 11.7 / 58,5 \u003d 0.2 mole.

If we are talking about gases, there is such a formula: n \u003d V / Vm, where N is the amount of substance ( mole), V is the volume of gas (L), Vm is the molar volume of gas. Under normal conditions (pressure 101 325 Pa and temperature 273 K), the molar volume of gas is the value of constant and is equal to 22.4 liters / mole. For example, what amount of substance will have nitrogen volume 30l under normal conditions? n (n2) \u003d 30 / 22.4 \u003d 1.34 mole.

Another formula: n \u003d n / na, where n is the amount of substance ( mole), N is the number of molecules, Na is constant avogadro, equal to 6.02 * 10 to 23 degrees (1 / mole). For example, what amount of substance is 1.204 * 10 to 23 degrees? We decide: n \u003d 1,204 * 10 at 23 degrees / 6.02 * 10 at 23 degrees \u003d 0.2 mole.

For any reaction equation, you can find the amount of substances that have entered the reaction and resulting from it. 2AGNO3 + Na2S \u003d AG2S + 2NanO3. From this equation it is clear that 2 mole Silver nitrate Provided from 1 mole Sodium sulfide, as a result of this formed 1 mole Sulfide of Silver and 2 mole Sodium nitrate. With these quantities of substances, you can find other values \u200b\u200brequired in tasks. We will consider the example.
To a solution containing silver nitrate weighing 25.5 g, a solution containing sodium sulphide was adhered. What amount of silver sulfide substance is formed?
At first we find the amount of silver nitrate substance, having previously calculated its molar mass. M (AGNO3) \u003d 170 g / mole. n (agno3) \u003d 25.5 / 170 \u003d 0.15 mole. The reaction equation for this problem is written above, it follows from it that of 2 mole Silver nitrate is formed 1 mole Sulfide of silver. Determine how much mole Sulfide silver is formed from 0.15 mole Silver Nitrate: N (Ag2S) \u003d 0.15 * 1/2 \u003d 0.075 mole.