Many owners of even the cleanest apartments periodically have to think about where the mole comes from. It seems that everything in the house is clean and there are no other insects, but these nondescript gray butterflies are beginning to be seen more and more often. In fact, the reason for the appearance of the moth depends primarily not on the cleanliness of the dwelling itself (as, for example, in the case of cockroaches), but on other factors.

The most important thing is what kind of mole started up in the house, to which type it belongs - there is a clothes mole and a food mole. These are similar to each other, but completely different in their biology, the pests enter the house each in their own ways.

Guessing where the mole comes from in the apartment, it is useful to remember that she does not care about the sanitary condition of the room. The pest equally effectively infects both non-hygienic barracks and elite housing. The main thing for her is the availability of food supply, namely, this food supply is most abundant in expensive homes.

The path of the food moth to the apartment

The moth's favorite food is cereals, seeds, nuts, dried fruits, dairy mixes, flour, animal feed, dried berries, herbs, and roots.

On a note

Very often, products in warehouses contaminated with moths are sold at bargain prices. Sometimes this means that by buying buckwheat or flour with a “holiday” discount, the housewife provides herself with a headache and bewilderment about the appearance of a moth in an apartment. It is important to remember that it does not appear in the kitchen by itself, in the overwhelming majority of cases, the owners of the room themselves bring it in.

Sometimes the reasons for the appearance of moths in the house become clear after a conversation with neighbors: the pest moves through the ventilation systems passing through the house. This means that the mole in your apartment may well appear from the next room.

A mole is a bad flyer, and it rarely moves between apartments. Much more often, larvae, pupae, and moth eggs enter the house with food or furniture.

If there is a grocery store on the first floor of a residential building, perhaps it is the place where the food mole in an apartment building comes from. Storage of cereals and flour in warehouses in large quantities provokes the reproduction of this pest.

Like any other winged, it may simply fly into an apartment, for example, from the landing through an open door, but this happens extremely rarely.

How does the mole of the apartment get into the apartment?

So where does the mole come from in the closet, if all things are new, clean and neatly folded? To find out, you should remember whether the following products have been bought recently:

  • natural wool carpets
  • furniture with natural upholstery
  • fur or wool outerwear
  • woolen or knitwear
  • shoes with natural fur.

If a mole started up at home after one of these purchases, then we can safely say that the larvae were already in it at the time of purchase. After settling the mole began to multiply and spoil other things that came across on her way. Unfortunately, the pest can even be in expensive things from proven stores that protect their reputation.

Purchased in the store or used furniture can also serve as an excellent "vehicle" for transporting moth larvae to a new place of residence. This is especially true of old furniture, in which it is very easy to get to the “tasty” filler.

Fully insure against the appearance of a food moth in an apartment is unlikely to succeed, because to infect a kitchen it is enough to have one flown into individuals or one larva in packed groats. It is much more important to create conditions at home that do not allow the moth to multiply comfortably and spoil the food.

First, let's see what conditions for the food moth are the most favorable:


How to prevent moths from entering the house?

Anyone who knows well where the mole comes from in an apartment can competently approach prevention of its appearance in a dwelling.

To avoid the appearance of a clothes moth is possible only with the help of a thorough inspection of all new things that enter the house. Even if a fur coat or hat is purchased at an expensive store, it is worthwhile to carefully examine its outer and inner sides right there for damage by moth larvae. At home, you should hang out the purchased item on the balcony and leave it there for three days. It is worth doing it in clear sunny weather without dampness, so as not to spoil the fur or wool.

Lavender decomposed in a cupboard or orange peels (they need to be changed as they dry) will become a wonderful fragrant prevention of clothes moths; you can also put an open bottle of essential oil of any of these plants.

For lovers of finished products, you can offer special moth sections, which are hung in the closet and also have a pleasant aroma. The very fur coat, hat or carpet can be sprayed with moth spray - this is especially recommended when storing warm clothes in the summer season.

It is interesting

There are a few more ways to keep your favorite things from the clothes moth. Before storing them, you can impose them with fresh newspapers or put some strong cigarettes in your pockets (the moth does not like the smell of printing ink and tobacco, but it can last for a long time and spoil the pleasure of wearing things). Another good way is to freeze things or products. To do this, during the cold season they can be “forgotten” on the balcony for a few days, after which any mole will die. The central heating battery also works on small woolen and knitted items - socks, hats, sweaters.

Principles for the prevention of food moths are similar to the above. After coming from the grocery store you need to look at all the goods where the mole can start: cereals, dried fruits, nuts, dry spices, herbs. If nothing is found there, food can be stored in glass jars or linen bags.

Some popular recipes are advised to saturate the bags with pickle or just salt water. Definitely not worth storing grits or flour in an open factory package.

It is recommended to periodically ventilate kitchen cabinets and wipe the shelves with vinegar, lay lavender or orange peels in them. It is not recommended to purchase cereals and nuts in large quantities "in reserve", since the longer such a product is stored, the greater the chance of moths multiplying in it.

The mole does not cause such a negative as a cockroach, but its presence is unpleasant. That she can eat the only fur coat, spoil your favorite things or nibble the harvest. Therefore, the fight against pest is relevant, but you should first find it.

Favorite places moth

Prefers groceries. She eats everything without exception:

  • grain;
  • croup;
  • hot spices;
  • flour;
  • cookies;
  • sugar;
  • crackers, other products.

Each species has its own eating habits, but often food butterflies do not disdain anything. This means that a pest can be found in any dry food. The larva eats the product and weaves a silk cocoon. In the flour and cereal formed pellets and lumps, in the nuts you can find nests with a worm.

The food moth flies badly. It is not capable of moving between rooms independently, and it gets into the apartment with things or products.

What does a mole look like

These are insects belonging to the order of butterflies. Their appearance depends on the type. House "pests" are represented by the following species:

  • food;
  • wardrobe;
  • grain;
  • furniture butterfly.

The color is often inconspicuous - greenish, grayish. Sizes are small - up to 15 millimeters. Insect can nest in the house and in nature:

  • rye;
  • cabbage;
  • apple tree

You can find out in more detail by reading the relevant article on our website.


Butterfly Food Detection

For the moth caterpillar of this type is typical food solid food:

  • cabbage;
  • leaves, stems;
  • croup;
  • nuts.

In some cases, the adult individual has no oral apparatus, it lives less than a week.

The nest should be sought either in or near the products. Often this apple, cereals, cabbage. First, a small nest is formed. In it are the larvae.


Causes of

For the settlement of the apartment pests enough butterflies, which are fertilized. She flies into the apartment, where there are comfortable conditions for reproduction. There are 3 main ways of insect occurrence:

  • moves from the neighbors through the cracks, the entrance;
  • flies through an open window or door;
  • comes through with things shopping.

Signs of a pest

The presence of eggs indicates the presence of eggs. But to find them is quite difficult because of the small size. In the closet, if you look closely, you can see a large number of web threads and pupae.

Flying insects usually do not go unnoticed. If there are 2 or more individuals in an apartment, you should immediately arm yourself with a flashlight and begin exploring the room. Carefully check the places where cereals are stored, in things made from natural fabrics in the kitchen set.


How to protect a home

It is important to know how to protect against moths. Prevention will help protect the apartment from pests. Of the measures worth noting the following:

  • the use of special deterrents;
  • checking all food items after purchase;
  • purchase only those foods that can be eaten during the week;
  • you should not purchase products in places where products are sold at a very low price.

For moth there is no worse than herbs with a strong smell:

  • rosemary;
  • sagebrush;
  • lavender;
  • tansy.

You can also use:

  • horse chestnut;
  • vinegar;
  • orange peels;
  • strawberry or laundry soap.

How to get rid of food moths (video)

If you put a jar from a moth in a cupboard with lavender filled with semolina, the larvae will survive, and only butterflies will fear the explosive mixture. Preventive measures are recommended to conduct comprehensively.

Purpose: To acquaint students with the concepts of "amount of matter", "molar mass" to give an idea of ​​the Avogadro constant. Show the relationship of the amount of matter, the number of particles and Avogadro constant, as well as the relationship of the molar mass, the mass and amount of the substance. To teach to make calculations.

Type of lesson:lesson of learning and initial consolidation of new knowledge.

During the classes

I. Organizational moment

Ii. Check d / s on the topic: "Types of chemical reactions"

Iii. Learning new material

1. Amount of substance - mol

Substances react in strictly defined ratios. For example, to get the substance water you need to take so much hydrogen and oxygen so that for every two hydrogen molecules there is one oxygen molecule:

2H 2 + O 2 = 2H 2 O

To obtain the substance iron sulfide, you need to take so much iron and sulfur, so that each atom of iron has one sulfur atom.

To get the substance phosphorus oxide, you need to take as many phosphorus and oxygen molecules so that there are five oxygen molecules per four phosphorus molecules.

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

  • A mole is the amount of a substance that contains as many structural particles (atoms, molecules) as there are 12 grams of carbon.

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

  • 1 mole of 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 mol of iron (Fe) contains 6 · 10 23 molecules.

The task:  Using the information received, answer the questions:

a) how many oxygen atoms is contained in 1 mole of oxygen?

- 6 · 10 23 · 2 = 12 · 10 23 atoms.

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

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

Number 6 · 10 23 is called Avogadro constant  in honor of the Italian scientist of the 19th century and is designated NA. Units are atoms / mol or molecules / mol.

2. Solving problems on finding the amount of substance

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

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

v = N / NA

Task 1.  How many atoms are in 2 moles of sulfur?

N = 2 · 6 · 10 23 = 12 · 10 23 atoms.

Task 2.  How many atoms are in 0.5 moles of iron?

N = 0.5 · 6 · 10 23 = 3 · 10 23 atoms.

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

N = 5 · 6 · 10 23 = 30 · 10 23 molecules.

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

v =12 · 10 23/6 · 10 23 = 2 mol.

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

v =0.6 · 10 23/6 · 10 23 = 0.1 mol.

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

v =3 · 10 23/6 · 10 23 = 0.5 mol.

3. Molar mass

For chemical reactions, the amount of substance in moles must be considered.

Q: But in practice, how to measure 2, or 2.5 moles of a substance? In what units is it best to measure the mass of substances?

For convenience, the molar mass is used in chemistry.

The molar mass is the mass of one mole of a substance.

It is denoted - M. Measured in g / mol.

The molar mass is the ratio of the mass of a substance to the corresponding amount of a substance.

Molar mass 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 relative atomic or relative molecular weight?

Mr (S) = 32; M (S) = 32 g / mol - which corresponds to 1 pray sulfur

Mr (H 2 O) = 18; M (H 2 O) = 18 g / mol - which corresponds to 1 pray water.

4. Solving problems on finding the mass of matter

Task 7.  To determine the mass of 0.5 mol of iron.

Task 8.  To determine the mass of 0.25 mol of copper

Task 9.  Determine the mass of 2 mol of carbon dioxide (CO 2)

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

v =160/80 = 8 mol

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

v =30/18 = 1.66 mol

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

v =40/24 = 1.66 mol

Iv. Fastening

Front-end survey:

  1. What is the amount of substance?
  2. What is 1 mole of any substance?
  3. What is a molar mass?
  4. Does the concept of "mole of molecules" and "mole of atoms" differ?
  5. Explain on the example of the ammonia molecule NH3.
  6. Why is it necessary to know 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

To study the text of the paragraph, to make two tasks: to find the amount of substance; on finding the mass of matter.

Literature:

  1. Gara N.N. Chemistry. Lessons in grade 8: a guide for teachers. _ M .: Enlightenment, 2009.
  2. Rudzites G.E., Feldman F.G. Chemistry. Grade 8 .: A textbook for educational institutions - Moscow: Enlightenment, 2009.

In chemistry, the term " mole". This is the amount substanceswhich contains approximately 6.02214 * 10 ^ 23 of its elementary particles - molecules, ions or atoms. To facilitate the calculations, this huge number, which is called the Avogadro number, is often rounded to 6.022 * 10 ^ 23. Mole is measured in grams.

Instruction

To find mole substances, you need to remember a very simple rule: the mass of one mole of any substances  numerically equal to its molecular weight, only expressed in other quantities. How is the molecular weight determined? With the help of the periodic table you will know the atomic mass of each element that is part of the molecule substances. Next, you need to add the atomic mass, taking into account the index of each element and you get the answer.

For example, fertilizer widely used in agriculture, ammonium nitrate (or in another way ammonium nitrate). Formula of it substances  NH4NO3. How to determine what is equal to his mole? First, write down the empirical (i.e., general) formula substances: N2H4O3.

Calculate its molecular weight with the index of each element: 12 * 2 + 1 * 4 + 16 * 3 = 76 amu (atomic mass units). Consequently, its molar mass (that is, the mass of one mole) is also 76, only its dimension: gram / mole. The answer is: 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 gas mixture occupies a volume of approximately 22.4 liters. And you have 179.2 liters. Perform the calculation: 179.2 / 22.4 = 8. Therefore, this volume contains 8 moles of gas.

Dividing the mass known for the problem conditions by the number of moles, you will get: 352/8 = 44. Therefore, one mole  This gas weighs 44 grams - it is carbon dioxide, CO2.

If there is any amount of gas of mass M contained in volume V at a given temperature T and pressure P. It is required to determine its molar mass (that is, to find what its mole). The problem of the periodic equation of Mendeleev-Clapeyron will help you: PV = MRT / m, where m is the molar mass that we need to determine, and R is the universal gas constant equal to 8.31. By transforming the equation, get: m = MRT / PV. Substituting in the formula known values, you will find what is mole  gas.

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

Instruction

Having the mass and name of a substance, one can easily find the amount of a substance: n = m / M, where n is the amount of a substance ( mole), m is the mass of the substance (g), M is the molar mass of the substance (g / mole). For example, the mass of sodium chloride is 11.7 g, find the amount of the substance. To substitute the required values ​​in the formula, you need to find the molar mass of sodium chloride: M (NaCl) = 23 + 35.5 = 58.5 g / mole. Substitute: n (NaCl) = 11.7 / 58.5 = 0.2 mole.

If we are talking about gases, then the following formula holds: n = V / Vm, where n is the amount of a substance ( mole), V is the gas volume (l), Vm is the molar volume of gas. Under normal conditions (pressure 101 325 Pa and temperature 273 K) the molar volume of the gas is constant and equal to 22.4 l / mole. For example, how much of a substance will have a nitrogen volume of 30 liters under normal conditions? n (N2) = 30 / 22.4 = 1.34 mole.

Another formula: n = N / NA, where n is the amount of a substance ( mole), N is the number of molecules, NA is the Avogadro constant, equal to 6.02 * 10 to the 23 degree (1 / mole). For example, how much of a substance is 1,204 * 10 in 23 degrees? Decide: n = 1,204 * 10 to 23 degrees / 6.02 * 10 to 23 degrees = 0.2 mole.

By any reaction equation, you can find the number of substances that entered into the reaction and formed as a result of it. 2AgNO3 + Na2S = Ag2S + 2NaNO3. From this equation it is clear that 2 mole  silver nitrate has interacted with 1 mole  sodium sulfide, as a result of this formed 1 mole  silver sulphide and 2 mole  sodium nitrate. With the help of these quantities of substances, you can find other values ​​required in the tasks. Consider an example.
A solution containing sodium sulphide was added to a solution containing silver nitrate weighing 25.5 g. What is the amount of silver sulfide that forms?
First, we find the amount of a substance of silver nitrate, having previously calculated its molar mass. M (AgNO3) = 170 g / mole. n (AgNO3) = 25.5 / 170 = 0.15 mole. The reaction equation for this problem is written above, it follows from it that 2 mole  silver nitrate is formed 1 mole  silver sulfide. Determine how much mole  silver sulfide is formed from 0.15 mole silver nitrate: n (Ag2S) = 0.15 * 1/2 = 0.075 mole.

The concept of mole is used to measure chemicals. Let us find out the peculiarities of this quantity, we give examples of calculation tasks with her participation, we define the importance of this term.

Definition

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

Avogadro number

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

Amount of substance

A substance that consists of atoms contains the Avogadro number. For example, for the sodium atom it is 6 * 10 * 23 1 / mol. What is its designation? Moles in chemistry are denoted by the Greek letter “nu” or the Latin “n”. For mathematical calculations related to the amount of substance, use a mathematical formula:

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

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

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

For example, in order to determine the molar mass of a carbon dioxide molecule, it is necessary to carry out the following calculations:

M (CO2) = Ar (C) + 2Ar (O) = 12 + 2 * 16 = 44

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

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

When determining the molar mass of sulfuric acid, we summarize two relative atomic masses of hydrogen with one atomic mass of sulfur and four relative atomic masses of oxygen. Their values ​​can always be found in the periodic table. As a result, we get 98.

Mole chemistry allows you to carry out a variety of calculations related to chemical equations. All typical calculation tasks in inorganic and organic chemistry, which presuppose finding the mass and volume of substances, are solved precisely 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 moles of hydrogen atoms, one mole of phosphorus atoms, and four moles of oxygen atoms. Everything is quite simple. Mole in chemistry is the transition from the microcosm of molecules and atoms into the macrosystem with kilograms and grams.

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

For the solution, we use the relationship between the Avogadro number (the amount of a substance). We get:

16.5 * 6.022 * 1023 = 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 of the substance, taking advantage of its relationship with the relative molecular mass. We get:

N = 5/44 * 6.023 * 1023 = 6.8 * 1023 molecules.

Algorithm of problems on chemical equation

When calculating the mass or reaction products using the equation, a specific action algorithm is used. First, it is determined which of the starting materials is deficient. To do this, find their number in moles. Next, make the equation of the process, necessarily place the stereochemical coefficients. The initial data are recorded over the substances, the amount of the substance taken in moles (by coefficient) is indicated below them. If necessary, carry out the conversion of units of measurement, using the formulas. Next, make up the proportion and solve it in a mathematical way.

If a more difficult task is proposed, then the mass of the pure substance is preliminarily calculated, removing impurities, and then they start to determine its quantity (in moles). Not a single problem in chemistry related to the reaction equation is solved without such a magnitude as a mole. In addition, using this term, one can easily determine the number of molecules or atoms using the Avogadro constant number for such calculations. Settlement assignments are included in test questions in chemistry for graduates of primary and secondary schools.