Sometimes even in perfect clean apartment Mole is found. The owners are perplexed where it appears from. There is a feeling that insects are far away from nowhere. Harmful guests spoil the property and all sorts of products.

Information about finding moths in the apartment contains such sections:

How does mole appear in the apartment?

Considering the circumstances of the appearance of malicious insects in the apartment, it is useful to know what they are divided into 2 types:

• Handling.
• Food.

Although externally, they are very similar, but they appear for various reasons.

The emergence of food moth

Housing owners often torments the question: "Can mole arise in a dirty room?". The answer is no. At the appearance of insects absolutely does not affect the dirt or non-compliance with sanitary standards in the apartment. Mol is distributed in those places where you can eat delicious. In addition, it should be forgotten that the amateur to enjoy eating almost everything that he comes across.

The reasons for which mol food is started:

1. It falls into the apartment in products, which were infected with these pests in the store or in stock.
2. Flies through the holes of the ventilation from the neighbors.
3. Wares to the apartment through window or doorways.

Quite often in stores either in warehouses suppliers products are stored with sanitation violations. In this regard, it is necessary to exercise careful attitude to the efforts or to the fact that they are sold at a discount.
If the buyer takes on the shares of nuts, dried fruits, spices, dry food for pets, flour, seeds, cereals, root, the likelihood of voracious pests is great. This reason is the most common.
Moth drops around ventilation holes Also need to be considered. Therefore, these holes are desirable to cover with gauze or shallow mesh.
Mol flies badly. Therefore, penetration into the apartment through window or doorways is unlikely.

Appearance of wrapping moth

This type of moth is strongly enjoyed by natural products, mainly fur and woolen. And it does not matter how clean things are. The main thing is that they are located. The reasons for the penetration of the apartment of the wrapping:

• Mole falls in housing with infected products.
• Insects enter pets.

The source of the appearance of pupae and larvae of the pest is most often bought things both new and used. Even buying clothes in an expensive store does not guarantee the lack of unpleasant individuals.
Penetrating into the apartment, the voracious pest is accepted actively. As a result, indoors spoiled carpets, furniture, products made of fur, woolen clothing.
Not new Material Much more accessible to feed moths. Therefore, it is necessary to thoroughly check all the items of the wardrobe and the interior to the presence of pest larvae.

Hard moles can also "bring the dogs to visit" the following breeds:

• Truck-haired dachshund.
• Bobtail.
• South Russian Shepherd.
• Risenshnauzer.

Therefore, the owners of the pets above the breeds are needed to carefully care for their wool.
Behind shoes, clothing and carpets also need to follow, especially for:

• Furniture with natural upholstery.
• Knitted clothes.
• Natural wool carpets.
• Top clothes. Mostly spoils products from wool and fur.
• Fur shoes.

In addition, if "unpleasant guests" discovered in the apartment, you need to remember recent purchases. It is likely that it is these acquisitions that caused the emergence of malicious individuals.

How to find mole in the apartment?

Often about the presence of insects testify flying in the apartment of the moth. If they were noticed, it testifies to the presence of larvae in things and products. They managed to complete their life cycle and turned into butterflies. We must search depending on the species in the appropriate places.

Eggs moths are not so easy to detect. Although in the croups it is possible to consider the rankled rzhore and caterpillars-larvae. Holes appear on woolen things, and on fur products, specific paths and sand (excrement of larvae) are visible.

Searches for food moth

This individual lives in the kitchen. It dwells in all sorts of unaczzle or poorly tied bulk croups. In addition, the larvae can often be found in nuts, tea and dried fruits.

In order to detect a voracious insect, you need to carefully consider the contents of all tanks and packages with products located in the apartment. When the larvae is detected, then you should get rid of products with them. It is also necessary to make the processing of surfaces where these products were stored. To do this, you will need a sponge and cleaning agent.

Also mole may occur in a bad ventilated room with high humidity. Therefore, the apartment needs to systematically ventilate. And if the pests have already settled in the kitchen, then the ventilation must be made more often.

To avoid the re-appearance of food moth, you need to hide the cereals into a impermeable container or tied polyethylene bags, but so that they failed to cover the pest larvae.

Searches for wrapping moth

Many mistaken believes that the mole of the dressing feeds all the clothes. But it does not correspond to the truth. These incines eat not clothes, but left on it after carrying a particle of human skin. I.e, voracious pests Can settle not only in a fur coat of natural fur, but also in pants, sweaters, hats, etc.

Mole must start looking from the cabinet. In this place she likes most of all. First of all, you should explore all the cracks in search of larvae and butterflies. The cabinet is completely free from clothing that should be cleaned thoroughly.

Tip!
Hang clothes on the street for a couple of days so that the straight rays of the sun fall on it. Mole does not love it!

To get rid of larvae, you need to apply disinfectants, which include dichlofos.
After the cabinet, it should be inspecting and processing all cabinet furniture indoors. Then mole will not return.

What does mole eat?

The homemade part delivers a mass of inconvenience in the room in the bottom of the spoiled things, products, property.

Favorite food moths food

These insects are divided into several species. Therefore, they feed on products made of grain and flour. A different group of individuals loves dried fruits, sweets and confectionery products.

Assortment of products that prefers this type of moth:

• bread,
• dried fruits,
• pasta,
• chocolate,
• flour,
• flour baking
• cookies,
• nuts
• candy,
• croup
• seeds
• oat flakes.

Taste preferences moths

This pest is divided into wrapping, fur coat, woolen, carpet, furniture mole.

List of dyeing pray:

• knitwear
• blankets
• socks,
• products from bird feathers,
• knitted hats,
• furniture upholstery
• mittens,
• dublin
• fur shoes
• natural coats,
• felt slippers,
• felt boots,
• wool sweatshirts
• carpets.

This is not the entire list, because the insect eats everything that consists of natural fiber. The pest can even spoil underwear from synthetic if cotton is present or wool.
Also, the attack is exposed to long wearing clothes, in which the epidermis particles from the skin of a person.

On a note!
Do not hide clothes in polyethylene packages. If the mole chose a thing, it also spars such a material!

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 it determined? With the help of the Mendeleev table, you will learn the atomic mass of each element included 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.

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 Selitras weighs 76 grams.

Suppose you are given such a task. It is known that the mass of 179.2 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 gas, 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.

Helpful advice

In the calculations, rounded values \u200b\u200bof atomic elements atomic weights are commonly used. If higher accuracy is required, the rounding is unacceptable.

A. Rogadro in 1811, at the very beginning of the development of the atomic theory, it assumes that in an equal number of ideal gases at the same pressure and temperature contains the same number of molecules. Later, this assumption was confirmed and became the necessary consequence for the kinetic theory. Now this theory is called Avogadro.

Instruction

Video on the topic

To find the number of atoms in the substance, determine what it is for the substance. Then find it mass and molar mass. After that, the ratio of mass and molar mass multiply by the Nogadro number, which is equal to 6.022 * 1023.

You will need

• To determine the number of atoms in the substance, take the exact scales (lever or electronic), a table of Mendeleev, a pressure gauge, a thermometer.

Instruction

Determining the number of atoms in pure
Weigh the sample of the studied substance on the exact scales, the result will be obtained in grams. Make sure it consists of single-navel molecules. Then, using the Mendeleev table, find the molar mass of the studied substance, expressed in grams on the mole. To do this, find the element corresponding to the substance from which the body consists and write it down. It will be equal to the molar mass, expressed in grams on mole. For example, for iron (FE) is 55.845 g / mol. If the isotope is definitely known, for example, iron 55, then you can take an integer, clean isotopes are often radioactive. Then the mass of the substance divide on its molar mass, and the result multiply by 6.022 * 10 ^ 23. This will be the number of atoms in this mass of the substance.

Number of atoms in complex substance
If the substance consists of polyatomic molecules, for example, water, the molecule of which consists of one oxygen atom and two hydrogen atoms, make the following sequence of actions. Using the weights, find a sample mass. Then write it down its chemical formula, and using the Mendeleev table, find the molar mass of each of the atoms from which the molecule consists. In the case of water, it will be on mole, - 16 grams per mol. Since hydrogen 2 atoms, multiply the molar mass on this number, as a result, get a total molar mass of 18 grams per mol. Then mass in grams divide on the molar mass in grams on mole and multiply by 6.022 * 10 ^ 23. In a substance, this number multiplied by the number of atoms in one molecule (it is equal to the water 3).

Number of atoms in mixtures and alloys
If the substance is a mixture of several substances with known mass fractions, measure it total weight. Then find the masses of pure substances, multiplying the mass on the appropriate shares. For example, if the bronze contains 70% copper and 30%, but to obtain the mass of copper, multiply a sample mass by 0.7, and to obtain a tin mass of tin to multiply a sample mass by 0.3. Next, act as described in the preceding paragraphs.

Number of atoms in gas
If the gas is in normal (pressure 760 mm Hg. Art. And temperature 00c), determine the volume of this gas by geometric methods (for example, to find the volume of gas in a parallelepiped, multiply length, width and height), expressing it in cubic meters. The resulting number is divided by 0.0224 and multiply by 6.022 * 10 ^ 23. If the gas molecule is a double, multiply the result by 2.

If pressure, the volume and temperature of the gas (pressure gauge, and the temperature of the thermometer) are known, then find the product of pressure in Pascal to the volume in the cube. meters, divide the temperature in Kelvin, and the number 8.31. The resulting result multiply by 6.022 * 10 ^ 23 and the number of atoms in the gas molecule.

Video on the topic

note

How to find the number of atoms in the substance. To find the number of atoms in the substance, determine what it is for the substance. Then find it mass and molar mass. After that, the ratio of mass and molar mass multiply by the Nogadro number, which is equal to 6.022 * 1023. You will need.

Helpful advice

The method is based on the connection between the atomic (or molecular) mass of the crystalline substance, its density, the number of Avogadro and a certain coefficient, which is determined from the distances between atoms in the crystal lattice. Knowing this number, you can different ways, which were tried in 1908-1910, to find the number N. You can collect α-particles in the Faraday cylinder, measure their charge and dividing it by the number of particles, get the charge of each of them; Half it gives us an elementary charge for which the number N is already determined ...

Sources:

• how to determine the number of atoms

First define chemical composition and the aggregate state of the substance. If gas is examined, measure its temperature, volume and pressure or place in normal conditions and measure only the volume. After that, calculate quantity Molecules I. atoms. To determine quantity atoms In solid or liquid, find their mass and molar mass, and then quantity Molecules I. atoms.

You will need

• manometer, thermometer thermometer, scales and table, find out permanent Avogadro.

Instruction

After that, calculate its area. For this, the diameter is erecting into the second degree, divide on 4 and multiply by the number 3.14. Then, the volume of the drops subside the spot to which it spread (D \u003d V / S) is the diameter of one molecules Oils, because it is believed that it spreads through water until the thickness of the oil film becomes equal to one.

Video on the topic

In order to find mass One pray, determine the chemical formula of substance, and with the help of the periodic table of Mendeleev, calculate it. We calculate the mass of one praying, finding the ratio of the mass of the substance to its number. You can also find mass One mole by weight of one molecule of the substance. To determine the mass of one praying gas, use the Klapaireron Mendeleev equation.

You will need

• periodic Table of Mendeleev, Scales, Pressure Gauge and Thermometer

Instruction

Determination of the mass of one praying for a chemical formormulate the chemical formula of the molecule of the studied substance. Then, find periodic table Mendeleeva atomic of each element included in the molecule. If one enters the formula several times, multiply its atomic mass On the number of entries. Then summarize the resulting mass numbers. The result will be the molecule in atomic units of mass, which is numerical equal to the molar mass of this substance (that is, the mass of one pray) to mole.

Determining the mass of one praying on a known amount of substance if the amount of substance is moles, molar mass which you need to find, using the scales, find it actual mass, expressing it in grams. To determine the mass of one pray, mass Substances subside on its number M \u003d M / υ.

Determining the mass of one praying substance by weight of the molecule if a mass of one molecule of the substance is known, expressed in grams, find mass one praying, multiplying mass This molecule by the amount in one mole (Number of Avogadro), which is equal to 6.022 10 ^ 23, m \u003d M0 NA.

Definitions of the mass of one praying gas Take a sealed vessel of a known volume expressed in cubic. Pour gas from it, and weigh the scales. Put the gas in it, and again weigh, empty and filled cylinders and will be equal to the mass of the gas. Translate it in.
Measure the gas temperature in the cylinder, if after downloading to wait a bit, it comes with the ambient temperature, and transfer it to Kelvin, adding Celsius number 273 to the degrees. Measure gas pressure to a manometer in Pascal. Find molar mass Gas ( mass one pray) change mass Gas at its temperature and 8.31 (universal gas constant), and sharing the result to pressure values \u200b\u200band volume M \u003d M R T / (P V).

Sometimes the researchers have such a task: how to determine the number of atoms of a substance? Initially, it may seem solely difficult, because the number of atoms even in a tiny sample of any substance is simply a grandiose. How to calculate them?

Instruction

Suppose you need to calculate the number of atoms in a piece of clean - for example, copper or even gold. Yes, imagine yourself on the site of the great scientist Archimedes, to whom Tsar Gieron gave a completely different order, saying: "You know, Archimedes, in vain I suspected my jeweler in fraud, the crown was out of pure gold! Our royal majesty now wants to know atoms in it. "

The task of this Archimender would naturally wore a stupor, although he was. Well, you would have coped with her in two bills. First you need to precisely weigh the crown. Suppose she would have weighed 2 kg, that is, 2000 grams. Then, on the Mendeleev table, install a molar weight of gold (approximately 197 grams / mol.) To simplify the calculations, slightly round down to the biggest way - let it be 200 grams / mol. Consequently, in the ill-fated corner of exactly 10 moles of gold. Well, then take the universal number of Avogadro (6,022x1023), multiply by 10 and with a celebration, take the result of the King Gieron.

Substitute the values \u200b\u200bknown to you in the PV / RT fraction, the result found multiply to the Universal Number of Avogadro (6.022 * 1023) and obtain the amount of gas atoms at a given volume, pressure and temperature.

And if you need to calculate the number of atoms in the sample of a complex substance? And there is nothing particularly difficult. Weigh, then write its accurate chemical formula, with the help of the Mendeleev table, specify the molar mass of each component and calculate the exact molar mass of this complex substance (considering the elements indexes).

In chemistry, mole is used as a unit of the amount of substance. The substance has three characteristics: mass, molar mass and amount of substance. The molar mass is called the mass of one praying substance.

Instruction

One moth of one or another substance is its amount that contains so many structural units, how many atoms are contained in 0.012 kg of conventional (non-radioactive) isotope. To the structural units of the substance of the molecule, atoms, ions. When, in conditions of the problem, it is given with a relative atomic mass AR, from the formula of the substance, depending on the formulation of the problem, by implementing calculations, are either a mass of one praying of the same substance, or its molar mass. The relative atomic mass of Ar is called the value equal to the ratio of the average mass of the isotope of the element to 1/12 carbon mass.

The molar mass has both organic and substances. For example, calculate this parameter for W2O and CH3 water. First find the molar weight of the water:
M (H2O) \u003d 2AR (H) + AR (O) \u003d 2 * 1 + 16 \u003d 18 g / mol
Methane is organic gas. This is that its molecules include hydrogen and carbon atoms. In total, one molecule of this gas contains three hydrogen atoms and one carbon atom. Molar Mass this substance Calculate as follows:
M (CH3) \u003d Ar (C) + 2AR (H) \u003d 12 + 3 * 1 \u003d 15 g / mol
Similarly, count the molar masses of any other substances.

Also, a mass of one praying substance or molar mass is found, knowing the mass and the amount of substance. In this case, it is calculated as the ratio of the mass of the substance to its quantity. The formula is as follows:
M \u003d m / ν, where m is a molar mass, M - mass, ν - the amount of substance.
Molar mass Substances are expressed in grams or kilograms on mole. If there is a mass of a molecule of a substance, then knowing the number of Avogadro, one can find a mass of one praying substance as follows:
Mr \u003d Na * Ma, where Mr is a molar mass, Na is the number of Avogadro, Ma - the mass of the molecule.
For example, knowing the mass of the carbon atom, you can find the molar mass of this substance:
Mr \u003d Na * Ma \u003d 6.02 * 10 ^ 23 * 1,993 * 10 ^ -26 \u003d 12 g / mol

Video on the topic

The mass of 1 mol of the substance is called it with a molar mass and is indicated by the letter M. Units of measurement of the molar mass - g / mol. The method of calculating this magnitude depends on conditions.

You will need

• - Periodic system of chemical elements D.I. Mendeleev (Mendeleev Table);
• - Calculator.

Instruction

Video on the topic

Sources:

• Talitsa Mendeleev

One of the first concepts that the schoolboy faces when studying the course of chemistry is mole. This value displays the amount of substance in which a certain number of particles is constant Avogadro. The concept of "mole" was introduced in order to avoid complicated mathematical calculations with large numbers of the smallest particles.

Instruction

Determine the number of particles in 1 mol of substances. This value is a constant and is called constant avogadro. It is equal to Na \u003d 6.02 * 1023 mol-1. If you want to spend more accurate calculationsThe value of this value must be taken according to the information of the data committee for and the CODATA technology, which recalculates Permanent Avogadro and approves the most accurate values. For example, in 2011 it was accepted that Na \u003d 6.022 140 78 (18) × 1023 mol-1.

Calculate the value of mol, which is equal to the ratio of the number of particles of a given substance by the value of constant avogadro.

Determine the magnitude of the substance through its M. It has the dimension of g / mol and is equal to the relative molecular weight of the MR, which is determined by the Mendeleev table for each element located in the composition of the substance. For example, molar methane CH4 is equal to the sum of relative atomic masses and four hydrogen: 12+ 4x1. In the end, get that M (CH4) \u003d 16 g / mol. Next, examine the condition of the task and find out for which mass M of the substance it is necessary to determine the amount of mole. It will be equal to the ratio of mass to the molar mass.

Remember that the molar mass of the substance is determined by the quantitative and qualitative characteristics of its composition, therefore substances can have the same mole values \u200b\u200bat various masses.

Examine the conditions of the problem if it requires it to determine the amount of mole for a gaseous substance, then it can be calculated through volumes. In this case, it is necessary to find out the volume of V specified gas under conditions. After that, divide this value to the molar volume of Vm gas, which is a constant and under normal conditions is 22.4 l / mol.

Scientists at the congress in Karlsruhe (Germany) in the 1860s decided to call the atom the smallest indivisible particle of a substance that is the carrier of his chemical properties. The number of atoms even in the tiny, practically not distinguishable with the naked eye, the sample of the substance is not just a huge one - the grandiose. Is it possible to somehow calculate how many atoms are contained in one or another amount of substance?

A bad joke can play a location under your apartment grocery store or any catering establishment. Very often, it is illiterately secured conditions for storing flour or cereals in a warehouse or in the store: Stimulates the active distribution of residential house moths.

Accidentally fly mole in your apartment and with staircaseBut this is extremely rare. In any case, from wherever this insect appears in your home, it will cause a lot of harm in the kitchen and not only. Therefore, as soon as you have determined that you have a deal directly with the food mol, start acting.

Clothes moth

Handling mole in the apartment is also not uncommon. In addition, if this started in your closet, be sure: first of all natural fabrics are injured - fur and wool. For this kind of insects it does not matter what state is your favorite thing, it is charged or not.
The main thing for her, the presence of this gastronomic delicacy. There are two main penetration paths hard moth In your home:

• through already infected things;
• with your pets.

Suppose you have just purchased a nice thing and not on some market or sale, but in a presentable and popular boutique. And what from this? You still do not get a 100 percent guarantee of the absence of moths in an expensive store. Its larvae or dolls may be on any things that you will drive into your home. As a result, spoiled furniture upholstery and clothing, carpets and fur products. This kind of trouble can comprehend you even after a hike in an expensive store.

• bobtail;
• rizenshnauzer;
• harsh dachshund;
• south Russian Shepherd, etc.

If you are the owner of one of these creatures, secure your pet a full protection against moth.

If we talk about clothes and shoes, followed by a doubly, to the risk category include:

At the same time, if you have already squeezed in your apartment or a private house of this pest, try to determine if you made any purchases directly before that? It is possible that they served as the cause of moths in your home.

Prevention of appearance

You can get rid of wrapping moths in the house with the help of effective flavative funds. For example, decompose orange peels on the shelves in the cabinet (they must be updated after the final drying) or lavender. High efficiency is shown and essential oils. Moreover, it is not necessary to apply the means to the surface, it is enough just to leave on the shelf an outdoor bottle with one of the essential oils.

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.

v \u003d. N / NA

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 Massa

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 mole

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

v \u003d.40/24 \u003d 1.66 mol

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.

With the concept of "mole", each schoolboy faces, who begins to study chemistry. With more complex concepts, such as a concentration, the molarity of the solvent, it is hard to deal, not knowing what mol. It can be concluded that mole is one of the most important concepts in chemistry. Many tasks cannot be solved without determining the number of moles.

Definition

So what is moth in chemistry? Explanation is pretty simple: this unit in which the amount of substance is expressed, one of the units of C. The determination of what mol in chemistry can be formulated and thus: 1 mol equivalent contains structural particles in 12 g of carbon-12.

As it was found, in 12 g of this isotope contains the number of atoms, numerically equal to the constant Avogadro.

The origin of the concept

I understand a bit with what mole in chemistry with definitions, we turn to the history of this concept. As it is customary, the term "mole" introduced the German chemist Wilhelm Osvald, who received Nobel Prize In 1909. The word "mole" obviously comes from the word "molecule".

Interesting fact - Hypothesis Avogadro that same conditions In the same volumes of different gases, one and the same amount of the substance was put forward long before Oswald, and the constant itself was calculated by Avogadro even at the beginning of the XIX century. That is, at least the concept of "mole" and did not exist, the very idea of \u200b\u200bthe amount of substance was already.

Basic formulas

The amount of substance is different, depending on the data of the task. This species has the most common formula in which this value is expressed by the ratio of the mass to the molar mass:

It is worth saying that the amount of substance is the magnitude of the additive. That is, to calculate the value of this value for the mixture, you must first determine the amount of substance for each item it and fold them.

Another formula is applied if the number of particles is known:

If the task states that the process occurs under normal conditions, it is possible to use the following rule: under normal conditions, any gas occupies an invariant volume - 22.4 liters. Then you can use the following expression:

The amount of substance is expressed from the Klapairone equation:

Knowing what mole in chemistry and basic formulas for determining the amount of substance moles makes it possible to solve many tasks much faster. If the amount of substance is known, you can find a mass, volume, density and other parameters.