Metal in a series of stress after Н 2

Metal sulphate in max s.o.

+
+ +

Metal (rest)

+
+ +

HNO 3 concentrate

Metal nitrate in max s.d.

Metal (rest; Al, Cr, Fe, Co, Ni when heated)

Nitrate metal

la in max s.o.

+
+

Metal (the rest in the yard stresses up to H 2)

NO / N 2 O / N 2 / NH 3 (NH 4 NO 3)

on conditions

+

Metal (the rest in the series of stresses after H 2)

Fig. 2. INTERACTION OF ACIDS WITH METALS

SALTS

Salts - These are complex substances that dissociate in solutions with the formation of positively charged ions (cations - basic residues), with the exception of hydrogen ions, and negatively charged ions (anions - acid residues), other than hydroxides - ions.

1. Bases interact with acids to form salt and water:

Cu (OH) 2 + 2HCl = CuCl 2 + 2H 2 O

2.With acidic oxides, forming salt and water:

Ca (OH) 2 + CO 2 = CaCO 3 + H 2 O

3. Alkalis react with amphoteric oxides and hydroxides to form salt and water:

2NaOH + Cr 2 O 3 = 2NaCrO 2 + H 2 O

KOH + Cr (OH) 3 = KCrO 2 + 2H 2 O

4. Alkalis interact with soluble salts, forming either a weak base, or a precipitate, or a gas:

2NaOH + NiCl 2 = Ni (OH) 2 ¯ + 2NaCl

base

2KOH + (NH 4) 2 SO 4 = 2NH 3 + 2H 2 O + K 2 SO 4

Ba (OH) 2 + Na 2 CO 3 = BaCO 3 ¯ + 2NaOH

5. Alkalis react with some metals, which correspond to amphoteric oxides:

2NaOH + 2Al + 6H 2 O = 2Na + 3H 2

6. The action of alkali on the indicator:

OH - + phenolphthalein ® raspberry color

OH - + litmus ® blue color

7. Decomposition of some bases on heating:

Сu (OH) 2 ® CuO + H 2 O

Amphoteric hydroxides- chemical compounds exhibiting the properties of both bases and acids. Amphoteric hydroxides correspond to amphoteric oxides (see clause 3.1).

Amphoteric hydroxides are usually written in the form of a base, but they can also be represented as an acid:

Zn (OH) 2 Û H 2 ZnO 2

base to-that

Chemical properties of amphoteric hydroxides

1. Amphoteric hydroxides interact with acids and acidic oxides:

Be (OH) 2 + 2HCl = BeCl 2 + 2H 2 O

Be (OH) 2 + SO 3 = BeSO 4 + H 2 O

2. Interact with alkalis and basic oxides of alkali and alkaline earth metals:

Al (OH) 3 + NaOH = NaAlO 2 + 2H 2 O;

H 3 AlO 3 acid sodium meta-aluminate

(H 3 AlO 3 ® HAlO 2 + H 2 O)

2Al (OH) 3 + Na 2 O = 2NaAlO 2 + 3H 2 O

All amphoteric hydroxides are weak electrolytes

Salt

Salt Are complex substances consisting of metal ions and an acid residue. Salts are products of complete or partial replacement of hydrogen ions with metal (or ammonium) ions in acids. Salt types: medium (normal), acidic and basic.

Medium salts Are the products of complete replacement of hydrogen cations in acids with metal (or ammonium) ions: Na 2 CO 3, NiSO 4, NH 4 Cl, etc.

Chemical properties of medium salts

1. Salts interact with acids, alkalis and other salts, forming either a weak electrolyte or a precipitate; or gas:

Ba (NO 3) 2 + H 2 SO 4 = BaSO 4 ¯ + 2HNO 3

Na 2 SO 4 + Ba (OH) 2 = BaSO 4 ¯ + 2NaOH

CaCl 2 + 2AgNO 3 = 2AgCl¯ + Ca (NO 3) 2

2CH 3 COONa + H 2 SO 4 = Na 2 SO 4 + 2CH 3 COOH

NiSO 4 + 2KOH = Ni (OH) 2 ¯ + K 2 SO 4

base

NH 4 NO 3 + NaOH = NH 3 + H 2 O + NaNO 3

2. Salts interact with more active metals. The more active metal displaces the less active one from the salt solution (Appendix 3).

Zn + CuSO 4 = ZnSO 4 + Cu

Acidic salts Are products of incomplete replacement of hydrogen cations in acids with metal (or ammonium) ions: NaHCO 3, NaH 2 PO 4, Na 2 HPO 4, etc. Acid salts can only be formed with polybasic acids. Almost all acidic salts are readily soluble in water.

Obtaining acidic salts and converting them to medium

1. Acid salts are obtained by reacting an excess of acid or acidic oxide with a base:

H 2 CO 3 + NaOH = NaHCO 3 + H 2 O

CO 2 + NaOH = NaHCO 3

2. When an excess of acid interacts with a basic oxide:

2H 2 CO 3 + CaO = Ca (HCO 3) 2 + H 2 O

3. Acid salts are obtained from medium salts by adding acid:

Eponymous

Na 2 SO 3 + H 2 SO 3 = 2NaHSO 3;

Na 2 SO 3 + HCl = NaHSO 3 + NaCl

4. Acid salts are converted into medium ones using alkali:

NaHCO 3 + NaOH = Na 2 CO 3 + H 2 O

Basic salts Are products of incomplete substitution of hydroxo groups (OH - ) bases with an acidic residue: MgOHCl, AlOHSO 4, etc. Basic salts can be formed only by weak bases of polyvalent metals. These salts are usually difficult to dissolve.

Obtaining basic salts and converting them to medium

1. Basic salts are obtained by reacting an excess of a base with an acid or acidic oxide:

Mg (OH) 2 + HCl = MgOHCl¯ + H 2 O

hydroxy

magnesium chloride

Fe (OH) 3 + SO 3 = FeOHSO 4 ¯ + H 2 O

hydroxy

iron (III) sulfate

2. Basic salts are formed from medium salt with the addition of a lack of alkali:

Fe 2 (SO 4) 3 + 2NaOH = 2FeOHSO 4 + Na 2 SO 4

3. Basic salts are converted into medium ones by adding acid (preferably the one that corresponds to the salt):

MgOHCl + HCl = MgCl 2 + H 2 O

2MgOHCl + H 2 SO 4 = MgCl 2 + MgSO 4 + 2H 2 O

ELECTROLYTES

Electrolytes- these are substances that decompose into ions in solution under the influence of polar solvent molecules (H 2 O). According to their ability to dissociate (decay into ions), electrolytes are conventionally divided into strong and weak. Strong electrolytes dissociate almost completely (in dilute solutions), while weak electrolytes decompose into ions only partially.

Strong electrolytes include:

· Strong acids (see p. 20);

· Strong bases - alkalis (see p. 22);

· Almost all soluble salts.

Weak electrolytes include:

Weak acids (see p. 20);

· Bases - not alkali;

One of the main characteristics of a weak electrolyte is dissociation constant – TO ... For example, for a monobasic acid,

HA Û H + + A - ,

where, is the equilibrium concentration of H + ions;

- equilibrium concentration of anions of acid A - ;

- equilibrium concentration of acid molecules,

Or for a weak foundation,

MOH Û M + + OH - ,

,

where, - equilibrium concentration of cations M +;

- equilibrium concentration of OH hydroxide ions - ;

- equilibrium concentration of molecules of a weak base.

Dissociation constants of some weak electrolytes (at t = 25 ° C)

Bases (hydroxides)- complex substances, the molecules of which contain one or more hydroxy OH groups. Most often, the bases are composed of a metal atom and an OH group. For example, NaOH is sodium hydroxide, Ca (OH) 2 is calcium hydroxide, etc.

There is a base - ammonium hydroxide, in which the hydroxy group is attached not to the metal, but to the NH 4 + ion (ammonium cation). Ammonium hydroxide is formed by dissolving ammonia in water (the reaction of adding water to ammonia):

NH 3 + H 2 O = NH 4 OH (ammonium hydroxide).

The valence of the gyroxy group is 1. The number of hydroxyl groups in the base molecule depends on the valence of the metal and is equal to it. For example, NaOH, LiOH, Al (OH) 3, Ca (OH) 2, Fe (OH) 3, etc.

All the reasons - solids that have different colors. Some bases are readily soluble in water (NaOH, KOH, etc.). However, most of them do not dissolve in water.

Bases that are soluble in water are called alkalis. Alkali solutions are "soapy", slippery to the touch and rather caustic. Alkalis include hydroxides of alkali and alkaline earth metals (KOH, LiOH, RbOH, NaOH, CsOH, Ca (OH) 2, Sr (OH) 2, Ba (OH) 2, etc.). The rest are insoluble.

Insoluble bases- these are amphoteric hydroxides, which, when interacting with acids, act as bases, and with alkali behave like acids.

Different bases differ in their ability to split off hydroxy groups, therefore, they are divided into strong and weak bases.

Strong bases in aqueous solutions easily give up their hydroxy groups, while weak ones do not.

Chemical properties of bases

The chemical properties of bases are characterized by their ratio to acids, acid anhydrides and salts.

1. Affect indicators... Indicators change their color depending on interaction with different chemicals. In neutral solutions - they have one color, in acid solutions - another. When interacting with bases, they change their color: the indicator methyl orange turns yellow, the litmus indicator turns blue, and phenolphthalein becomes fuchsia.

2. Interact with acidic oxides with the formation of salt and water:

2NaOH + SiO 2 → Na 2 SiO 3 + H 2 O.

3. Reacts with acids, forming salt and water. The reaction of interaction of a base with an acid is called a neutralization reaction, since after its completion the medium becomes neutral:

2KOH + H 2 SO 4 → K 2 SO 4 + 2H 2 O.

4. React with salts, forming new salt and base:

2NaOH + CuSO 4 → Cu (OH) 2 + Na 2 SO 4.

5. Able to decompose when heated into water and basic oxide:

Cu (OH) 2 = CuO + H 2 O.

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The general properties of bases are due to the presence in their solutions of the OH - ion, which creates an alkaline medium in the solution (phenolphthalein turns crimson, methyl orange turns yellow, litmus turns blue).

1. Chemical properties of alkalis:

1) interaction with acidic oxides:

2KOH + CO 2 ®K 2 CO 3 + H 2 O;

2) reaction with acids (neutralization reaction):

2NaOH + H 2 SO 4 ®Na 2 SO 4 + 2H 2 O;

3) interaction with soluble salts (only if, under the action of alkali on the soluble salt, a precipitate forms or gas is released):

2NaOH + CuSO 4 ®Cu (OH) 2 ¯ + Na 2 SO 4,

Ba (OH) 2 + Na 2 SO 4 ®BaSO 4 ¯ + 2NaOH, KOH (conc.) + NH 4 Cl (crystal) ®NH 3 + KCl + H 2 O.

2. Chemical properties of insoluble bases:

1) interaction of bases with acids:

Fe (OH) 2 + H 2 SO 4 ® FeSO 4 + 2H 2 O;

2) decomposition on heating. Insoluble bases decompose on heating into basic oxide and water:

Cu (OH) 2 ®CuO + H 2 O

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All topics in this section:

Getting the grounds
1. Obtaining alkalis: 1) interaction of alkali or alkaline earth metals or their oxides with water: Ca + 2H2O®Ca (OH) 2 + H

Nomenclature of acids
Acid names are derived from the element from which the acid is derived. In this case, the name of anoxic acids usually has the ending -hydrogen: HCl - hydrochloric, HBr - hydrobromic

Chemical properties of acids
The general properties of acids in aqueous solutions are due to the presence of H + ions formed during the dissociation of acid molecules, thus, acids are proton donors: HxAn «xH +

Getting acids
1) interaction of acid oxides with water: SO3 + H2O®H2SO4, P2O5 + 3H2O®2H3PO4;

Chemical properties of acidic salts
1) acidic salts contain hydrogen atoms capable of taking part in the neutralization reaction, so they can react with alkalis, turning into medium or other acidic salts - with a lower number

Getting acidic salts
An acidic salt can be obtained: 1) by the reaction of incomplete neutralization of a polybasic acid with a base: 2H2SO4 + Cu (OH) 2®Cu (HSO4) 2 + 2H

Basic salts.
Basic (hydroxosalts) are salts that are formed as a result of incomplete replacement of hydroxide ions of the base with acid anions. Mono acid bases, e.g. NaOH, KOH,

Chemical properties of basic salts
1) basic salts contain hydroxo groups that can take part in the neutralization reaction, so they can react with acids, transforming into medium salts or into basic salts with less

Obtaining basic salts
The basic salt can be obtained: 1) by the reaction of incomplete neutralization of the base with an acid: 2Cu (OH) 2 + H2SO4® (CuOH) 2SO4 + 2H2

Medium salts.
Medium salts are the products of complete replacement of the H + -ions of the acid with metal ions; they can also be considered as products of complete substitution of ОН-ions of the anion base

Nomenclature of medium salts
In the Russian nomenclature (used in technological practice), there is the following order of naming medium salts: the word is added to the root of the name of the oxygen-containing acid

Chemical properties of medium salts
1) Almost all salts are ionic compounds, therefore, in a melt and in an aqueous solution, they dissociate into ions (when current is passed through solutions or molten salts, the electrolysis process takes place).

Obtaining medium salts
Most of the methods for obtaining salts are based on the interaction of substances of the opposite nature - metals with non-metals, acid oxides with basic, bases with acids (see table 2).

The structure of the atom.
An atom is an electrically neutral particle consisting of a positively charged nucleus and negatively charged electrons. The ordinal number of an element in the Periodic Table of Elements is equal to the charge of the nucleus

Composition of atomic nuclei
The nucleus is made up of protons and neutrons. The number of protons is equal to the ordinal number of the element. The number of neutrons in the nucleus is equal to the difference between the mass number of the isotope and

Electron
Electrons revolve around the nucleus along certain stationary orbits. Moving in its orbit, the electron does not emit or absorb electromagnetic energy. Radiation or absorption of energy occurs

The rule for filling in electronic levels, sublevels of elements
The number of electrons that can be at one energy level is determined by the formula 2n2, where n is the number of the level. The maximum filling of the first four energy levels: for the first

Ionization energy, electron affinity, electronegativity.
Ionization energy of an atom. The energy required to detach an electron from an unexcited atom is called the first ionization energy (potential) I: E + I = E + + e- Ionization energy

Covalent bond
In most cases, when a bond is formed, the electrons of the bonded atoms are socialized. This type of chemical bond is called a covalent bond (the prefix "co-" in Latin

Sigma and pi communication.
Sigma (σ) -, pi (π) -bonds - an approximate description of the types of covalent bonds in molecules of various compounds, σ-bond is characterized by the fact that the density of the electron cloud is maximum

Formation of a covalent bond by the donor-acceptor mechanism.
In addition to the homogeneous mechanism of covalent bond formation described in the previous section, there is a heterogeneous mechanism - the interaction of oppositely charged ions - the proton H + and

Chemical bond and geometry of molecules. BI3, PI3
Figure 3.1 Addition of dipole elements in NH3 and NF3 molecules

Polar and non-polar communication
A covalent bond is formed as a result of the sharing of electrons (with the formation of common electron pairs), which occurs during the overlap of electron clouds. In education

Ionic bond
Ionic bond is a chemical bond that occurs through the electrostatic interaction of oppositely charged ions. Thus, the process of education and

Oxidation state
Valence 1. Valence is the ability of atoms chemical elements form a certain number of chemical bonds. 2. The valence values ​​vary from I to VII (rarely VIII). Valent

Hydrogen bond
In addition to various heteropolar and homeopolar bonds, there is another special type of bond that has attracted more and more attention from chemists over the past two decades. This is the so-called vodoro

Crystal lattices
So, the crystal structure is characterized by the correct (regular) arrangement of particles in strictly defined places in the crystal. When mentally connecting these points with lines, a space is obtained

Solutions
If crystals of table salt, sugar or potassium permanganate (potassium permanganate) are placed in a vessel with water, then we can observe how the amount of solid matter gradually decreases. At the same time, water,

Electrolytic dissociation
Solutions of all substances can be divided into two groups: electrolytes-conduct electricity, non-electrolyte conductors are not. This division is conditional, because all

Dissociation mechanism.
Water molecules are dipole, i.e. one end of the molecule is negatively charged, the other positively. A molecule with a negative pole approaches a sodium ion, a positive pole approaches a chlorine ion; surround io

Ionic product of water
Hydrogen exponent (pH) is a value that characterizes the activity or concentration of hydrogen ions in solutions. The pH is indicated by pH. Hydrogen exponent numerically

Chemical reaction
A chemical reaction is the transformation of some substances into others. However, such a definition needs one essential addition. In a nuclear reactor or in an accelerator, some substances are also converted

Methods for placing the coefficients in the OVR
Electronic balance method 1). Write down the chemical reaction equation KI + KMnO4 → I2 + K2MnO4 2). Find atoms, change

Hydrolysis
Hydrolysis is a process of exchange interaction of salt ions with water, leading to the formation of low-dissociated substances and accompanied by a change in the reaction (pH) of the medium. The essence

Chemical reaction rate
The reaction rate is determined by the change in the molar concentration of one of the reacting substances: V = ± ((C2 - C1) / (t2 - t

Factors affecting the rate of chemical reactions
1. The nature of the reacting substances. The nature of chemical bonds and the structure of reagent molecules play an important role. Reactions proceed in the direction of the destruction of less strong bonds and the formation of substances with

Activation energy
The collision of chemical particles leads to chemical interaction only if the colliding particles have an energy exceeding a certain certain value. Consider mutual

Catalyst catalyst
Many reactions can be accelerated or slowed down by the introduction of certain substances. The added substances do not participate in the reaction and are not consumed during its course, but have a significant effect on

Chemical equilibrium
Chemical reactions that proceed at comparable rates in both directions are called reversible. In such reactions, equilibrium mixtures of reagents and products are formed, the composition of which

Le Chatelier's principle
Le Chatelier's principle says that in order to shift the balance to the right, one must, first, increase the pressure. Indeed, with an increase in pressure, the system will "resist" an increase in the

Factors affecting the rate of chemical reaction
Factors affecting the rate of a chemical reaction Increase the rate Decrease the rate Presence of chemically active reagents

Hess's law
Using table values

Heat effect
In the course of the reaction, the bonds in the starting materials are broken and new bonds are formed in the reaction products. Since the formation of a bond proceeds with the release, and its breaking - with the absorption of energy, then x

Metal and hydroxyl group (OH). For example, sodium hydroxide - NaOH, calcium hydroxide - Ca(OH) 2 , barium hydroxide - Ba(OH) 2, etc.

Getting hydroxides.

1. Exchange reaction:

CaSO 4 + 2NaOH = Ca (OH) 2 + Na 2 SO 4,

2. Electrolysis of aqueous solutions of salts:

2KCl + 2H 2 O = 2KOH + H 2 + Cl 2,

3. Interaction of alkali and alkaline earth metals or their oxides with water:

K + 2H 2 O = 2 KOH + H 2 ,

Chemical properties of hydroxides.

1. Hydroxides are alkaline in nature.

2. Hydroxides dissolve in water (alkali) and are insoluble. For instance, KOH- dissolves in water, and Ca(OH) 2 - slightly soluble, has a solution white... Metals of the 1st group of the periodic table D.I. Mendeleev give soluble bases (hydroxides).

3. Hydroxides decompose when heated:

Cu(OH) 2 = CuO + H 2 O.

4. Alkalis react with acidic and amphoteric oxides:

2KOH + CO 2 = K 2 CO 3 + H 2 O.

5. Alkalis can react differently with some non-metals at different temperatures:

NaOH + Cl 2 = NaCl + NaOCl + H 2 O(cold),

NaOH + 3 Cl 2 = 5 NaCl + NaClO 3 + 3 H 2 O(heat).

6. Interact with acids:

KOH + HNO 3 = KNO 3 + H 2 O.