“Mass fraction of a substance” - Density. Denoted by Vm. Мср = ?1 M1 + ?2 M2 + ?3 M3 + ... volume fraction? = V1 / Vtot. Denoted w. Calculated in shares or percentages. Molar concentration: c (in-va) = n (in-va) / Vsystem in mol/l. Relative density is calculated in relative units.). The density of any substance is calculated by the formula? = m/V, usually measured in g/ml or g/l.
“Ferromagnetic fluid” - Ferromagnetic fluid is a “smart” fluid. Application: converting the energy of vibrational motion into electrical energy. Video. MAOU Siberian Lyceum. “I am inspired by life itself, nature itself. Application: electronic devices. Ferromagnetic fluid can reduce friction. Application: magnetic separation of ores.
“Magnetic properties of matter” - Ferrites have high magnetization values and Curie temperatures. where is the coefficient of proportionality, which characterizes the magnetic properties of a substance and is called the magnetic susceptibility of the medium. Some materials retain their magnetic properties even in the absence of an external magnetic field. Magnetic moment of an electron and an atom Atom in an external magnetic field.
“Structure of the substance of the molecule” - CH3OH + HBr. CH3?CH2?NO2. Mutual influence of atoms in molecules using the example of aniline. + 2Na. CH3OH + NaOH. S2n6. CH4. HC?C?CH2?CH3. Structural. Isomers -. 2nd position. Theory of chemical structure A.M. Butlerov. Increase in basic properties.
"Dispersed systems" - Aerosols. According to the state of aggregation of the dispersion medium and the dispersed phase. Dispersion medium: Gelatinous sediments formed during the coagulation of sols. Press any key. Gels. Natural water always contains dissolved substances. Classification of disperse systems. Solutions. Dispersed phase: Suspensions.
“Pure substances and mixtures” - 1. A mixture is: ? Conclusions: What types of mixtures are there? Filtration. Calcium phosphate. Pure substances and mixtures. ZnO, ZnCl2, H2O. SO3, MgO, CuO. A pure substance has constant physical properties (tboil, tmelt, ?, etc.). Distillation (distillation). Methods for separating mixtures. In what ways can mixtures be separated?
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What then is a solution?
Solution (true solution) – a homogeneous system in which the particle size of the substance is less than 1 nm; there is no interface between the particles and the medium.
Any solution consists of:
- Solute
- Solvent
From two or more components of a solution solvent is the one taken in more quantity and has the same state of aggregation as the solution as a whole.
Types of aqueous solutions
Water + Solid
(CaCl 2 in H 2 O)
Water + Liquid substance
(H 2 SO 4 in H 2 O)
Water + Solid
How does dissolution occur?
Diffusion
The process of penetration of some molecules of a substance through others.
sugar molecules (white circles)
water molecules (dark circles)
Thermal phenomena during the dissolution of substances
Destruction of chemical and intermolecular bonds between ions, atoms or molecules of a dissolving substance and uniform distribution (diffusion) of the resulting particles between water molecules.
energy consumption
Endothermic process
Interaction of particles of a solute with a solvent.
energy release
Exothermic process
Dissolution is a physical and chemical process in which, along with the formation of a conventional mechanical mixture of substances, there is a process of interaction between particles of a dissolved substance and a solvent.
Solubility
Solubility is the ability of substances to dissolve in water or other solvent.
Substances
Highly soluble
Slightly soluble
Insoluble
Solubility coefficient (S) is the maximum number of g of a substance that can dissolve in 100 g of solvent at a given temperature.
Saturated solution is a solution that is in dynamic equilibrium with the solute.
- a solution in which a given substance no longer dissolves at a given temperature
Factors affecting solubility
- Nature of the solvent
- Nature of the solute
- Pressure
- Temperature
Solution concentration
Solution concentration is the content of a substance in a certain mass or volume of solution.
Mass fraction of solute in solution is the ratio of the mass of the solute to the mass of the solution.
Expression of solution concentration
Molarity - the number of moles of dissolved substance in 1 liter of solution
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These are homogeneous (uniform) systems consisting of two or more components and products of their interaction.
Precise determination of solution (1887 D.I. Mendeleev)
Solution– homogeneous (homogeneous) system consisting of
dissolved particles
substance, solvent
and products
their interactions.
Solutions are divided:
- Molecular – aqueous solutions of non-electrolytes
(alcohol solution of iodine, glucose solution).
- Molecular ionic – solutions of weak electrolytes
(nitrous and carbonic acids, ammonia water).
3. Ionic solutions – solutions of electrolytes.
1g Practically Insoluble S" width="640" Solubility –
the property of a substance to dissolve in water or other solution.
Solubility coefficient(S) is the maximum number of g of a substance that can dissolve in 100 g of solvent at a given temperature.
Substances.
Slightly soluble
S =0.01 – 1 g
Highly soluble
Practically Insoluble
S 
Influence of various factors on solubility.
Temperature
Pressure
Solubility
Nature of solutes
Nature of the solvent
Solubility of liquids in liquids depends in a very complex way on their nature.
Three types of liquids can be distinguished, differing in their ability to mutually dissolve.
- Practically immiscible liquids, i.e. incapable of forming mutual solutions(for example, H 2 0 and Hg, H 2 0 and C 6 H 6).
2) Liquids that can be mixed in any ratio, i.e. with unlimited mutual solubility(for example, H 2 0 and C 2 H 5 OH, H 2 0 and CH 3 COOH).
3) Liquids with limited mutual solubility(H 2 0 and C 2 H 5 OS 2 H 5, H 2 0 and C 6 H 5 NH 2).
Significant Impact pressure affects only the solubility of gases.
Moreover, if no chemical interaction occurs between the gas and the solvent, then according to
Henry's law: the solubility of a gas at a constant temperature is directly proportional to its pressure above the solution
Methods of expressing the composition of solutions 1. shares 2. Concentrations
Mass fraction of solute in solution– the ratio of the mass of the solute to the mass of the solution. (fractions of a unit/percent)
Solution concentration –
Molarity- the number of moles of dissolved substance in 1 liter of solution.
ʋ - amount of substance (mol);
V – solution volume (l);
Equivalent concentration (normality) – the number of equivalents of a dissolved substance in 1 liter of solution.
ʋ eq. - number of equivalents;
V – volume of solution, l.
Expression of concentrations of solutions.
Molal concentration (molality)– number of moles of solute per 1000 g of solvent.
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Solutions (dispersed systems) Solutions are physicochemical dispersed systems consisting of two or more components.
3 slide
Dispersed system, phase, medium In solutions, particles of one substance are uniformly distributed in another substance, a dispersed system arises. The dissolved substance is called the dispersed phase, and the substance in which the dispersed phase is distributed is called the dispersion medium (solvent).
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Based on the particle size of the dispersed phase, solutions are divided into: Coarsely dispersed systems (suspensions) are heterogeneous systems (inhomogeneous). The particle sizes of this phase range from 10⁻⁵ to 10⁻⁷m. Not stable and visible to the naked eye (suspensions, emulsions, foams, powders).
5 slide
Based on the particle size of the dispersed phase, solutions are divided into: Colloidal solutions (finely dispersed systems or sols) are microheterogeneous systems. Particle size ranges from 10⁻⁷ to 10⁻⁹m. The particles are no longer visible to the naked eye, but the system is not stable. Depending on the nature of the dispersion medium, sols are called hydrosols - dispersion medium - liquid, aerosols - dispersion medium air.
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Based on the particle size of the dispersed phase, solutions are divided into: True solutions (molecular dispersed and ion dispersed systems). They are not visible to the naked eye. The particle sizes are 10ˉ8 cm, i.e. equal to the sizes of molecules and ions. In such systems, heterogeneity disappears - the systems become homogeneous and stable, and true solutions are formed. These include solutions of sugar, alcohol, non-electrolytes, electrolytes and weak electrolytes.
7 slide
Solubility Solubility is the ability of a given substance to dissolve in a given solvent and under given conditions. Solubility depends on several factors: the nature of the solvent and solute; on temperature; from pressure. If the solvent molecules are non-polar or low-polar, then this solvent will dissolve substances with non-polar molecules well. It will be worse to dissolve with greater polarity. And it will practically not happen with the ionic type of bond.
8 slide
Solubility Polar solvents include water and glycerin. Low-polar alcohol and acetone. To non-polar chloroform, ether, fats, oils.
Slide 9
Solubility of gases The solubility of gases in liquids increases with increasing pressure and decreasing temperature. When heated, the solubility of gases decreases, but by boiling, the solution can be completely freed from gas. Gases are more soluble in non-polar solvents.
10 slide
Solubility of a liquid The solubility of a liquid in a liquid increases with increasing temperature and is practically independent of pressure. In liquid-liquid systems, when there is limited solubility of 1 liquid in 2 and 2 in 1, separation is observed. As the temperature increases, solubility increases and at some temperatures complete mutual dissolution of these liquids occurs. This temperature is called the critical solution temperature and above it, separation is not observed.
11 slide
Solubility of solids The solubility of solids in liquids depends little on temperature and is independent of pressure. A liquid is a solvent and can dissolve substances until a certain concentration is reached, which cannot be increased, no matter how long the contact between the solvent and the dissolved substance occurs. When equilibrium is thus achieved, the solution is called saturated.
12 slide
A solution in which the concentration of the solute is less than in a saturated solution, and in which, under given conditions, some more of it can be dissolved, is called an unsaturated solution. A solution that, under given conditions, contains more dissolved substance than in a saturated solution; the excess substance easily precipitates is called a supersaturated solution.
Slide 13
Mendeleev's hydrate theory By the end of the 19th century, 2 opposing points of view on the nature of a solution had formed: physical and chemical. Physical theory considered solutions as mixtures formed as a result of crushing a soluble substance in a solvent environment without chemical action between them. Chemical theory considered the process of solution formation as a chemical interaction between the molecules of the solute and the molecules of the solvent.
Slide 14
Mendeleev's hydration theory Molecules of a liquid solvent enter into solvation interaction with molecules of a solute having a crystal lattice. Solvation is the process of interaction between solvent molecules and the solute. Solvation in aqueous solutions is called hydration. The molecular aggregates formed as a result of solvation are called solvates (in the case of water, hydrates). In contrast to solviosis, the combination of homogeneous particles in a solution is called association.
