Then we get:

Solving this equation, we find: x 1 = 3 and x 2 = 1.25. But x 1 = 3 does not satisfy the condition of the problem.
Therefore, = 1.25 + 1 = 2.25 mol / l.

12.1. In which of the following reactions will an increase in pressure shift the equilibrium to the right? Justify the answer.

1) 2 NH 3 (g) 3 H 2 (g) + N 2 (d)

2) ZnCO 3 (q) ZnO (q) + CO 2 (d)

3) 2HBr (g) H 2 (g) + Br 2 (g)

4) CO 2 (d) + C (graphite) 2CO (g)

12.2.At a certain temperature, the equilibrium concentrations in the system

2HBr (g) H 2 (g) + Br 2 (d)

Chemical reversibility. reactions. Chemical equilibrium and conditions for its displacement, practical application.

All chemical reactions can be divided into reversible and irreversible.

Reversible reactions are incomplete: in a reversible reaction, none of the reactants is completely consumed. The reversible reaction can proceed both in forward and reverse directions. Reversible chemical reactions are written as one chemical equation with a reversibility sign:.

The reaction going from left to right is called straight reaction, and from right to left - reverse .

Most chemical reactions are reversible. For example, a reversible reaction is the interaction of hydrogen with iodine vapor:

Initially, when the starting materials are mixed, the rate of the forward reaction is high, and the rate of the reverse reaction is zero. As the reaction proceeds, the starting materials are consumed and their concentrations decrease. As a result, the speed of the direct reaction decreases. At the same time, reaction products appear and their concentration increases. Therefore, a reverse reaction begins to occur, and its speed gradually increases. When the rates of the forward and reverse reactions become the same, chemical equilibrium.

The state of chemical equilibrium is influenced by: 1) the concentration of substances

2) temperature

3) pressure

When one of these parameters changes, the chemical equilibrium is violated and the concentrations of all reactants will change until a new equilibrium is established. Such a transition of the system from one state to another is called displacement. The direction of the displacement of chemical equilibrium is determined by the principle

Le Chatelier: " If any effect is exerted on a system in chemical equilibrium, then as a result of the processes occurring in it, the equilibrium will shift in such a direction that the effect exerted will decrease. "... For example, when one of the substances participating in the reaction is introduced into the system, the equilibrium shifts towards the consumption of this substance. As the pressure rises, it shifts so that the pressure in the system decreases. As the temperature rises, the equilibrium shifts towards the endothermic reaction, the temperature in the system decreases.

Irreversible reactions are those that go on to the end. – until one of the reactants is completely consumed. Conditions for the irreversibility of chemical reactions:

Chemical equilibrium is inherent reversible reactions and is not typical for irreversible chemical reactions.

Often, when exercising chemical process, the initial reactants are completely converted into the reaction products. For example:

Cu + 4HNO 3 = Cu (NO 3) 2 + 2NO 2 + 2H 2 O

It is impossible to obtain metallic copper by conducting the reaction in the opposite direction, because given the reaction is irreversible... In such processes, the reagents are completely converted into products, i.e. the reaction proceeds to the end.

But the bulk of chemical reactions reversible, i.e. the parallel course of the reaction in the forward and reverse directions is likely. In other words, the reagents only partially pass into products and the reaction system will consist of both reagents and products. The system in this case is in the state chemical equilibrium.

In reversible processes, at first the direct reaction has a maximum rate, which gradually decreases due to a decrease in the amount of reagents. The reverse reaction, on the contrary, initially has a minimum rate, which increases as the products accumulate. In the end, a moment comes when the rates of both reactions become equal - the system comes to a state of equilibrium. When equilibrium occurs, the concentrations of the components remain unchanged, but the chemical reaction does not stop. That. Is a dynamic (mobile) state. For clarity, we give the following figure:

Let's say some reversible chemical reaction:

a A + b B = c C + d D

then, proceeding from the law of mass action, we write down expressions for straightυ 1 and reverseυ 2 reactions:

υ1 = k 1 · [A] a · [B] b

υ2 = k 2 · [C] c · [D] d

Capable of chemical equilibrium, the forward and reverse reaction rates are equal, i.e .:

k 1 · [A] a · [B] b = k 2 · [C] c · [D] d

we get

TO= k 1 / k 2 = [C] c · [D] d ̸ [A] a · [B] b

Where K =k 1 / k 2 – equilibrium constant.

For any reversible process, under given conditions k is a constant value. It does not depend on the concentration of substances, because when the amount of one of the substances changes, the amounts of other components also change.

When the conditions of the chemical process change, the equilibrium may shift.

Factors affecting balance shift:

• changes in the concentration of reagents or products,
• pressure change,
• temperature change,
• introducing the catalyst into the reaction medium.

Le Chatelier's principle

All of the above factors affect the shift in chemical equilibrium, which obeys Le Chatelier principle: if you change one of the conditions under which the system is in equilibrium — concentration, pressure, or temperature — then equilibrium will shift in the direction of the reaction that opposes this change. Those. equilibrium tends to shift in the direction leading to a decrease in the influence of the impact, which led to a violation of the state of equilibrium.

So, let us consider separately the influence of each of their factors on the state of equilibrium.

Influence changes in the concentration of reagents or products let's show by example Haber process:

N 2 (g) + 3H 2 (g) = 2NH 3 (g)

If, for example, nitrogen is added to an equilibrium system consisting of N 2 (g), H 2 (g) and NH 3 (g), then the equilibrium should shift in a direction that would contribute to a decrease in the amount of hydrogen towards its initial value, those. towards education additional quantity ammonia (to the right). At the same time, a decrease in the amount of hydrogen will also occur. When hydrogen is added to the system, the equilibrium will also shift towards the formation of a new amount of ammonia (to the right). Whereas the introduction of ammonia into the equilibrium system, according to Le Chatelier principle , will cause a shift in equilibrium towards the process that is favorable for the formation of initial substances (to the left), i.e. the concentration of ammonia should be reduced by decomposing some of it into nitrogen and hydrogen.

A decrease in the concentration of one of the components will shift the equilibrium state of the system towards the formation of this component.

Influence pressure changes it makes sense if gaseous components take part in the process under study and there is a change in the total number of molecules. If the total number of molecules in the system remains permanent, then the pressure change does not affect on its balance, for example:

I 2 (g) + H 2 (g) = 2HI (g)

If the total pressure of the equilibrium system is increased by decreasing its volume, then the equilibrium will shift in the direction of decreasing volume. Those. in the direction of decreasing the number gas in system. In reaction:

N 2 (g) + 3H 2 (g) = 2NH 3 (g)

from 4 gas molecules (1 N 2 (g) and 3 H 2 (g)) 2 gas molecules are formed (2 NH 3 (g)), i.e. the pressure in the system decreases. As a result, an increase in pressure will contribute to the formation of an additional amount of ammonia, i.e. the balance will shift towards its formation (to the right).

If the temperature of the system is constant, then a change in the total pressure of the system will not lead to a change in the equilibrium constant TO.

Temperature change system affects not only the displacement of its equilibrium, but also the equilibrium constant TO. If an equilibrium system, at constant pressure, is supplied with additional heat, then the equilibrium will shift towards the absorption of heat. Consider:

N 2 (g) + 3H 2 (g) = 2NH 3 (g) + 22 kcal

So, as you can see, the direct reaction proceeds with the release of heat, and the reverse - with absorption. With an increase in temperature, the equilibrium of this reaction shifts towards the reaction of decomposition of ammonia (to the left), because it is and weakens the external influence - an increase in temperature. On the contrary, cooling leads to a shift in equilibrium in the direction of ammonia synthesis (to the right), since the reaction is exothermic and counteracts cooling.

Thus, the rise in temperature favors the displacement chemical equilibrium in the direction of the endothermic reaction, and the temperature drop - in the direction of the exothermic process . Equilibrium constants all exothermic processes decrease with increasing temperature, and endothermic processes increase.

Chemical equilibrium is maintained as long as the conditions in which the system is located remain unchanged. Changes in conditions (concentration of substances, temperature, pressure) cause imbalance. After some time, chemical equilibrium is restored, but under new conditions that are different from the previous ones. Such a transition of the system from one equilibrium state to another is called displacement(shift) balance. The direction of displacement follows the Le Chatelier principle.

With an increase in the concentration of one of the initial substances, the equilibrium shifts towards a higher consumption of this substance, and the direct reaction intensifies. A decrease in the concentration of the starting substances shifts the equilibrium towards the formation of these substances, since the reverse reaction is enhanced. An increase in temperature shifts the equilibrium towards the endothermic reaction, with a decrease in temperature, towards an exothermic reaction. An increase in pressure shifts the equilibrium towards a decrease in the amount of gaseous substances, that is, towards smaller volumes occupied by these gases. On the contrary, with a decrease in pressure, the equilibrium shifts towards an increase in the amount of gaseous substances, that is, towards large volumes formed by gases.

EXAMPLE 1.

How will an increase in pressure affect the equilibrium state of the following reversible gas reactions:

a) SO 2 + C1 2 = SO 2 CI 2;

b) H 2 + Br 2 = 2HBr.

Solution:

We use Le Chatelier's principle, according to which an increase in pressure in the first case (a) shifts the equilibrium to the right, towards a smaller amount of gaseous substances occupying a smaller volume, which weakens the external effect of the increased pressure. In the second reaction (b), the amount of gaseous substances, both initial and reaction products, are equal, as are the volumes occupied by them, therefore, the pressure does not affect and the equilibrium is not disturbed.

EXAMPLE 2.

In the ammonia synthesis reaction (–Q) 3H 2 + N 2 = 2NH 3 + Q, the direct reaction is exothermic, and the reverse is endothermic. How should the concentration of reactants, temperature and pressure be changed to increase the yield of ammonia?

Solution:

To shift the balance to the right, you must:

a) increase the concentration of H 2 and N 2;

b) lower the concentration (removal from the reaction sphere) NH 3;

c) lower the temperature;

d) increase the pressure.

Example 3.

The homogeneous reaction of the interaction of hydrogen chloride and oxygen is reversible:

4HC1 + O 2 = 2C1 2 + 2H 2 O + 116 kJ.

1. What impact on the equilibrium of the system will have:

a) an increase in pressure;

b) temperature rise;

c) the introduction of the catalyst?

Solution:

a) In accordance with Le Chatelier's principle, an increase in pressure leads to a shift in equilibrium towards a direct reaction.

b) An increase in t ° leads to a shift in equilibrium towards the opposite reaction.

c) The introduction of the catalyst does not shift the equilibrium.

2. In what direction will the chemical equilibrium shift if the concentration of reactants is doubled?

Solution:

υ → = k → 0 2 0 2; υ 0 ← = k ← 0 2 0 2

After increasing the concentrations, the rate of the direct reaction became:

υ → = k → 4 = 32 k → 0 4 0

that is, it increased in comparison with the initial speed by 32 times. Likewise, the speed of the reverse reaction increases by a factor of 16:

υ ← = k ← 2 2 = 16k ← [H 2 O] 0 2 [C1 2] 0 2.

The increase in the speed of the forward reaction is 2 times higher than the increase in the speed of the reverse reaction: the equilibrium shifts to the right.

EXAMPLE 4.

V which side will the equilibrium of the homogeneous reaction shift:

PCl 5 = PC1 3 + Cl 2 + 92 kJ,

if the temperature is increased by 30 ° C, knowing that the temperature coefficient of the forward reaction is 2.5, and the reverse one is 3.2?

Solution:

Since the temperature coefficients of the forward and reverse reactions are not equal, an increase in temperature will have a different effect on the change in the rates of these reactions. Using the van't Hoff rule (1.3), we find the rates of forward and reverse reactions when the temperature rises by 30 ° C:

υ → (t 2) = υ → (t 1) = υ → (t 1) 2.5 0.1 · 30 = 15.6υ → (t 1);

υ ← (t 2) = υ ← (t 1) = υ → (t 1) 3.2 0.1 30 = 32.8υ ← (t 1)

An increase in temperature increased the rate of the forward reaction by 15.6 times, and the reverse one by 32.8 times. Consequently, the equilibrium will shift to the left, towards the formation of PCl 5.

EXAMPLE 5.

How will the rates of forward and reverse reactions change in an isolated system C 2 H 4 + H 2 ⇄ C 2 H 6 and where will the equilibrium shift when the volume of the system increases by 3 times?

Solution:

The initial rates of forward and backward reactions are as follows:

υ 0 = k 0 0; υ 0 = k 0.

An increase in the volume of the system causes a decrease in the concentration of reactants by 3 times, hence the change in the rate of forward and reverse reactions will be as follows:

υ 0 = k = 1 / 9υ 0

υ = k = 1 / 3υ 0

The decrease in the rates of forward and reverse reactions is not the same: the rate of the reverse reaction is 3 times (1/3: 1/9 = 3) higher than the rate of the reverse reaction, therefore the equilibrium will shift to the left, towards the side where the system occupies a larger volume, that is, towards the formation of C 2 H 4 and H 2.

Chemical equilibrium and principles of its displacement (Le Chatelier principle)

V reversible reactions under certain conditions, a state of chemical equilibrium can occur. This is a condition in which the speed of the reverse reaction becomes equal to the speed of the forward reaction. But in order to shift the equilibrium in one direction or another, it is necessary to change the conditions of the reaction. The principle of displacement of equilibrium is Le Chatelier's principle.

Key points:

1. External influence on a system in a state of equilibrium, leads to a shift of this equilibrium in the direction at which the effect of the effect produced is weakened.

2. With an increase in the concentration of one of the reacting substances, the equilibrium shifts towards the consumption of this substance; with a decrease in the concentration, the equilibrium shifts towards the formation of this substance.

3. With an increase in pressure, the equilibrium shifts towards a decrease in the amount of gaseous substances, that is, towards a decrease in pressure; with a decrease in pressure, the equilibrium shifts towards an increase in the amount of gaseous substances, that is, towards an increase in pressure. If the reaction proceeds without changing the number of molecules of gaseous substances, then the pressure does not affect the position of equilibrium in this system.

4. When the temperature rises, the equilibrium shifts towards the endothermic reaction, with a decrease in temperature, towards the exothermic reaction.

For the principles we thank the manual "Principles of Chemistry" N.Ye. Kuzmenko, V.V. Eremin, V.A.Popkov.

USE tasks for chemical equilibrium (formerly A21)

Task number 1.

H2S (g) ↔ H2 (g) + S (g) - Q

1. Increasing pressure

2. Rising temperature

3. Reducing pressure

Explanation: to begin with, consider the reaction: all substances are gases and there are two product molecules on the right side, and only one on the left, the reaction is also endothermic (-Q). Therefore, consider the change in pressure and temperature. We need the equilibrium to shift towards the reaction products. If we increase the pressure, then the equilibrium will shift towards a decrease in volume, that is, towards the reagents - this does not suit us. If we increase the temperature, then the equilibrium will shift towards the endothermic reaction, in our case towards the products, which is what was required. The correct answer is 2.

Task number 2.

Chemical equilibrium in the system

SO3 (g) + NO (g) ↔ SO2 (g) + NO2 (g) - Q

will shift towards the formation of reagents when:

1. An increase in NO concentration

2. An increase in SO2 concentration

3. Rising temperature

4. Increase in pressure

Explanation: all substances are gases, but the volumes on the right and left sides of the equation are the same, so the pressure on the equilibrium in the system will not affect. Consider the change in temperature: as the temperature rises, the equilibrium shifts towards the endothermic reaction, just towards the reagents. The correct answer is 3.

Task number 3.

In system

2NO2 (g) ↔ N2O4 (g) + Q

a shift in balance to the left will help

1. Increase in pressure

2. Increase in N2O4 concentration

3. Lowering the temperature

4. Catalyst introduction

Explanation: we draw attention to the fact that the volumes of gaseous substances in the right and left sides of the equation are not equal, therefore, a change in pressure will affect the equilibrium in this system. Namely, with increasing pressure, the equilibrium shifts towards a decrease in the amount of gaseous substances, that is, to the right. It doesn't suit us. The reaction is exothermic, therefore, a change in temperature will affect the equilibrium of the system. With a decrease in temperature, the equilibrium will shift towards the exothermic reaction, that is, also to the right. With an increase in the concentration of N2O4, the equilibrium shifts towards the consumption of this substance, that is, to the left. The correct answer is 2.

Task number 4.

In reaction

2Fe (s) + 3H2O (g) ↔ 2Fe2O3 (s) + 3H2 (g) - Q

the equilibrium will shift towards the reaction products at

1. Increasing pressure

2. Adding a catalyst

3. Added iron

4. Adding water

Explanation: the number of molecules in the right and left parts is the same, so that a change in pressure will not affect the equilibrium in this system. Consider an increase in the concentration of iron - the equilibrium should shift towards the consumption of this substance, that is, to the right (towards the reaction products). The correct answer is 3.

Task number 5.

Chemical equilibrium

H2O (l) + C (s) ↔ H2 (g) + CO (g) - Q

will shift towards the formation of products in the case

1. Pressure rise

2. Temperature rise

3. Increasing the time of the process

4. Applications of the catalyst

Explanation: a change in pressure will not affect the equilibrium in this system, since not all substances are gaseous. As the temperature rises, the equilibrium shifts towards the endothermic reaction, that is, to the right (towards the formation of products). The correct answer is 2.

Task number 6.

As the pressure rises, the chemical equilibrium will shift towards the products in the system:

1.CH4 (g) + 3S (s) ↔ CS2 (g) + 2H2S (g) - Q

2.C (t) + CO2 (g) ↔ 2CO (g) - Q

3.N2 (g) + 3H2 (g) ↔ 2NH3 (g) + Q

4.Ca (HCO3) 2 (t) ↔ CaCO3 (t) + CO2 (g) + H2O (g) - Q

Explanation: the change in pressure does not affect reactions 1 and 4, therefore not all participating substances are gaseous, in equation 2 in the right and left sides of the number of molecules are the same, so the pressure will not affect. Equation 3 remains. Let us check: with increasing pressure, the equilibrium should shift towards a decrease in the amount of gaseous substances (4 molecules on the right, 2 molecules on the left), that is, towards the reaction products. The correct answer is 3.

Task number 7.

Does not affect balance shift

H2 (g) + I2 (g) ↔ 2HI (g) - Q

1. Raising pressure and adding catalyst

2. Raising the temperature and adding hydrogen

3. Lowering the temperature and adding hydrogen iodide

4. Adding iodine and adding hydrogen

Explanation: in the right and left parts of the amount of gaseous substances are the same, therefore, a change in pressure will not affect the equilibrium in the system, nor will the addition of a catalyst, because as soon as we add a catalyst, the direct reaction will accelerate, and then immediately the reverse and the equilibrium in the system will be restored ... The correct answer is 1.

Task number 8.

To shift the equilibrium to the right in the reaction

2NO (g) + O2 (g) ↔ 2NO2 (g); ΔH °<0

required

1. Introduction of the catalyst

2. Lowering the temperature

3. Decrease in pressure

4. Decrease in oxygen concentration

Explanation: a decrease in oxygen concentration will lead to a shift in equilibrium towards the reactants (to the left). A decrease in pressure will shift the equilibrium towards a decrease in the amount of gaseous substances, that is, to the right. The correct answer is 3.

Task number 9.

Product yield in exothermic reaction

2NO (g) + O2 (g) ↔ 2NO2 (g)

with a simultaneous increase in temperature and decrease in pressure

1. Increase

2. Will decrease

3. Will not change

4. First it will increase, then it will decrease

Explanation: with an increase in temperature, the equilibrium shifts towards the endothermic reaction, that is, towards the products, and with a decrease in pressure, the equilibrium shifts towards an increase in the amount of gaseous substances, that is, also to the left. Therefore, the product yield will decrease. The correct answer is 2.

Task number 10.

Increasing the yield of methanol in the reaction

CO + 2H2 ↔ CH3OH + Q

promotes

1. Temperature rise

2. Introduction of the catalyst

3. Administration of the inhibitor

4. Increase in pressure

Explanation: with increasing pressure, the equilibrium shifts towards the endothermic reaction, that is, towards the reagents. An increase in pressure shifts the equilibrium towards a decrease in the amount of gaseous substances, that is, towards the formation of methanol. The correct answer is 4.

Self-help assignments (answers below)

1. In the system

CO (g) + H2O (g) ↔ CO2 (g) + H2 (g) + Q

a shift in chemical equilibrium towards the reaction products will contribute to

1. Decrease in pressure

2. Increase in temperature

3. Increasing the concentration of carbon monoxide

4. Increase in hydrogen concentration

2. In which system, with increasing pressure, the equilibrium shifts towards the reaction products

1.2CO2 (g) ↔ 2CO (g) + O2 (g)

2.C2H4 (g) ↔ C2H2 (g) + H2 (g)

3.PCl3 (g) + Cl2 (g) ↔ PCl5 (g)

4.H2 (g) + Cl2 (g) ↔ 2HCl (g)

3. Chemical equilibrium in the system

2HBr (g) ↔ H2 (g) + Br2 (g) - Q

will shift towards the reaction products at

1. Increasing pressure

2. Rising temperature

3. Reducing pressure

4. Using the catalyst

4. Chemical equilibrium in the system

С2Н5ОН + СН3СООН ↔ СН3СООС2Н5 + Н2О + Q

shifts towards the reaction products at

1. Adding water

2. Reducing the concentration of acetic acid

3. Increasing the concentration of ether

4. When removing the ester

5. Chemical equilibrium in the system

2NO (g) + O2 (g) ↔ 2NO2 (g) + Q

shifts towards the formation of the reaction product at

1. Increasing pressure

2. Rising temperature

3. Reducing pressure

4. Application of the catalyst

6. Chemical equilibrium in the system

CO2 (g) + C (s) ↔ 2CO (g) - Q

will shift towards the reaction products at

1. Increasing pressure

2. Lowering the temperature

3. Increase in CO concentration

4. Rising temperature

7. Changes in pressure will not affect the state of chemical equilibrium in the system.

1.2NO (g) + O2 (g) ↔ 2NO2 (g)

2.N2 (g) + 3H2 (g) ↔ 2NH3 (g)

3.2CO (g) + O2 (g) ↔ 2CO2 (g)

4.N2 (g) + O2 (g) ↔ 2NO (g)

8. In which system, with increasing pressure, the chemical equilibrium will shift towards the starting substances?

1.N2 (g) + 3H2 (g) ↔ 2NH3 (g) + Q

2.N2O4 (g) ↔ 2NO2 (g) - Q

3.CO2 (g) + H2 (g) ↔ CO (g) + H2O (g) - Q

4.4HCl (g) + O2 (g) ↔ 2H2O (g) + 2Cl2 (g) + Q

9. Chemical equilibrium in the system

C4H10 (g) ↔ C4H6 (g) + 2H2 (g) - Q

will shift towards the reaction products at

1. Temperature rise

2. Lowering the temperature

3. Using a catalyst

4. Reducing the concentration of butane

10. On the state of chemical equilibrium in the system

H2 (g) + I2 (g) ↔ 2HI (g) -Q

does not affect

1. Increase in pressure

2. Increase in iodine concentration

3. Increase in temperature

4. Decrease in temperature

2016 assignments

1. Establish a correspondence between the chemical reaction equation and the shift in chemical equilibrium with increasing pressure in the system.

Reaction equation Chemical equilibrium shift

A) N2 (g) + O2 (g) ↔ 2NO (g) - Q 1. Shifts towards the direct reaction

B) N2O4 (d) ↔ 2NO2 (d) - Q 2. Shifts towards the reverse reaction

C) CaCO3 (tv) ↔ CaO (tv) + CO2 (g) - Q 3. There is no shift in equilibrium

D) Fe3O4 (s) + 4CO (g) ↔ 3Fe (s) + 4CO2 (g) + Q

2. Establish a correspondence between the external influence on the system:

CO2 (g) + C (s) ↔ 2CO (g) - Q

and a shift in chemical equilibrium.

A. Increase in CO concentration 1. Shifts towards a direct reaction

B. Decrease in pressure 3. There is no shift in equilibrium

3. Establish a correspondence between the external influence on the system

HCOOH (l) + C5H5OH (l) ↔ HCOOC2H5 (l) + H2O (l) + Q

External influence Displacement of chemical equilibrium

A. Addition of UNCOO 1. Shifts towards a direct reaction

B. Dilution with water 3. No displacement of equilibrium

D. Temperature rise

4. Establish a correspondence between the external influence on the system

2NO (g) + O2 (g) ↔ 2NO2 (g) + Q

and a shift in chemical equilibrium.

External influence Displacement of chemical equilibrium

A. Decrease in pressure 1. Shifts towards direct reaction

B. Increase in temperature 2. Shifts towards reverse reaction

B. Increase in NO2 temperature 3. No displacement of equilibrium

D. O2 addition

5. Establish a correspondence between the external influence on the system

4NH3 (g) + 3O2 (g) ↔ 2N2 (g) + 6H2O (g) + Q

and a shift in chemical equilibrium.

External influence Displacement of chemical equilibrium

A. Decrease in temperature 1. Shift towards the direct reaction

B. Increase in pressure 2. Shifts towards reverse reaction

B. Increase in concentration in ammonia 3. There is no shift in equilibrium

D. Removal of water vapor

6. Establish a correspondence between the external influence on the system

WO3 (tv) + 3H2 (g) ↔ W (tv) + 3H2O (g) + Q

and a shift in chemical equilibrium.

External influence Displacement of chemical equilibrium

A. Temperature rise 1. Shifts towards a direct reaction

B. Increase in pressure 2. Shifts towards reverse reaction

B. Use of catalyst 3. No displacement of equilibrium

D. Removal of water vapor

7. Establish a correspondence between the external influence on the system

C4H8 (g) + H2 (g) ↔ C4H10 (g) + Q

and a shift in chemical equilibrium.

External influence Displacement of chemical equilibrium

A. Increase in hydrogen concentration 1. Shifts towards a direct reaction

B. Temperature rise 2. Shifts towards reverse reaction

B. Increase in pressure 3. There is no shift in equilibrium

D. Use of catalyst

8. Establish a correspondence between the equation of a chemical reaction and a simultaneous change in the parameters of the system, leading to a shift in chemical equilibrium towards the direct reaction.

Reaction equation Changing system parameters

A. H2 (g) + F2 (g) ↔ 2HF (g) + Q 1. Increase in temperature and hydrogen concentration

B. H2 (g) + I2 (tv) ↔ 2HI (g) -Q 2. Decrease in temperature and hydrogen concentration

B. CO (g) + H2O (g) ↔ CO2 (g) + H2 (g) + Q 3. Increase in temperature and decrease in hydrogen concentration

G. C4H10 (g) ↔ C4H6 (g) + 2H2 (g) -Q 4. Decrease in temperature and increase in hydrogen concentration

9. Establish a correspondence between the chemical reaction equation and the shift in chemical equilibrium with increasing pressure in the system.

Reaction equation Direction of displacement of chemical equilibrium

A. 2HI (g) ↔ H2 (g) + I2 (s) 1. Shifts towards the direct reaction

B. C (g) + 2S (g) ↔ CS2 (g) 2. Shifts towards the reverse reaction

B. C3H6 (g) + H2 (g) ↔ C3H8 (g) 3. No shift in equilibrium occurs

G. H2 (g) + F2 (g) ↔ 2HF (g)

10. Establish a correspondence between the equation of a chemical reaction and a simultaneous change in the conditions for its implementation, leading to a shift in chemical equilibrium towards the direct reaction.

Reaction equation Changing conditions

A. N2 (g) + H2 (g) ↔ 2NH3 (g) + Q 1. Increase in temperature and pressure

B. N2O4 (l) ↔ 2NO2 (g) -Q 2. Decrease in temperature and pressure

B. CO2 (g) + C (s) ↔ 2CO (g) + Q 3. Increase in temperature and decrease in pressure

D. 4HCl (g) + O2 (g) ↔ 2H2O (g) + 2Cl2 (g) + Q 4. Decrease in temperature and increase in pressure

Answers: 1 - 3, 2 - 3, 3 - 2, 4 - 4, 5 - 1, 6 - 4, 7 - 4, 8 - 2, 9 - 1, 10 - 1

1. 3223

2. 2111

3. 1322

4. 2221

5. 1211

6. 2312

7. 1211

8. 4133

9. 1113

10. 4322

For assignments we thank the collections of exercises for 2016, 2015, 2014, 2013 authors:

Kavernin A.A., Dobrotina D.Yu., Snastinu M.G., Savinkina E.V., Zhveinova O.G.