How the concentration changes with increasing temperature. The conditions of displacement of equilibrium of reversible reactions
The reversible reactions themselves are rarely practical interest, but in some cases the technological benefit or profitability of production require the balance of equilibrium to one or another reverse reaction. To shift equilibrium use technological techniques such as change concentration of reagents, change in pressure, temperature.
An increase in the concentration of one of the reacting substances (or both substances) displays the balance towards the formation of the reaction products. Or, on the contrary, a decrease in the concentration of the reaction products also shifts the balance towards their formation. For example, for the reaction:
H 2 + Cl 2 ↔2hcl;
Increasing the concentration of H 2 or CL 2 (as well as at the same time H 2 and CL 2) or a decrease in the concentration of NCl will lead to a displacement of this equilibrium from left to right, and to dismiss the equilibrium to the right, it is necessary or to increase the concentration of HCL or reduce the concentrations H 2, CL 2 or Both substances.
The effect of changes in pressure on the reversible reaction will consider on the example of the reaction:
2N 2 + H 2 ↔2NZ;
With increasing pressure on this system Concentration of substances increases. In this case, equilibrium will shift towards smaller volumes. In the left side of the equation, two nitrogen volumes react with one volume of hydrogen. In the right part of the equation there are two ammonia volumes, i.e. The amount of volumes in the right-hand side of the equilibrium reaction is less than in the left and, therefore, with an increase in pressure, the reaction equilibrium will shift to the right. For reaction:
H 2 + BR 2 ↔2HBR
The number of volumes in the right and in the left side of the equation is equal (one hydrogen volume and one volume of bromine on the left and two volumes of hydrogen bromide on the right) and an increase in pressure will not lead to a displacement of equilibrium neither to the right or right to left. If an equilibrium reaction is given:
Cl 2 (R) + 2HJ (R) ↔2HCl (R) + J 2 (TB)
The indices (g) correspond to gaseous substances, and (TV) - the substance in the solid phase. Changing the pressure on this equilibrium system will affect gaseous substances (CL 2, HJ, HCL), and on substances that are in solid state (J2) or in liquid (H20) pressure does not affect. Therefore, for the above reaction, the increase in pressure will shift equilibrium towards smaller volumes, i.e. from left to right.
Increase temperature increases the kinetic energy of all molecules involved in the reaction. But the reaction molecules (endothermic) begin to interact with each other faster. With an increase in temperature, the equilibrium is shifted towards the endothermic reaction, with a decrease in temperature - towards an exometric reaction. Consider an equilibrium reaction:
Q SASOZ ↔CAO + CO 2 -Q
in which the left side corresponds to the exothermic reaction, and the right-endothermal. When it heated the SASOZ, the decomposition of this substance occurs, therefore, the higher the decomposition temperature of the SASOZ, the concentration of SAO and CO 2 becomes greater, the equilibrium is shifted to the endothermic part of the equation, that is, from left to right, and on the contrary, with a decrease in temperature, the equilibrium will shift towards the exothermic reaction, those. from right to left.
Changes occurring in the equilibrium system as a result of external influences are determined by the principle of Le Chateel
"If there is an external impact on the system in chemical equilibrium, it leads to a displacement of equilibrium to the direction opposing this effect."
The introduction into the equilibrium system of catalysts does not lead to a displacement of equilibrium.
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Main article: Principle Le Chatelu - Brown
The position of chemical equilibrium depends on the following reaction parameters: temperature, pressure and concentration. The impact that these factors have on a chemical reaction are subject to the patterns that were expressed in general In 1885, the French scientist leschatel.
Factors affecting chemical equilibrium:
1) Temperature
With increasing temperature, the chemical equilibrium is shifted towards the endothermic (absorption) of the reaction, and with a decrease in the exothermic (selection) of the reaction.
CaCo. 3 \u003d Cao + Co 2 -Q t →, t ↓ ←
N. 2 + 3h. 2 ↔2Nh. 3 + Q T ←, t ↓ →
2) Pressure
With an increase in pressure, the chemical equilibrium shifts towards a smaller volume of substances, and with a decrease in the side of the larger volume. This principle is valid only for gases, i.e. If solids are involved in the reaction, they are not taken into the calculation.
CaCo. 3 \u003d Cao + Co 2 P ←, p ↓ →
1mol \u003d 1mol + 1mol
3) Concentration of starting materials and reaction products
With an increase in the concentration of one of the initial substances, the chemical equilibrium is shifted towards the reaction products, and with an increase in the concentration of reaction products, towards the starting materials.
S. 2 + 2O. 2 \u003d 2SO. 2 [S], [o] →, ←
Catalysts do not affect chemical equilibrium shift!
The main quantitative characteristics of the chemical equilibrium: the chemical equilibrium constant, the degree of transformation, the degree of dissociation, equilibrium output. Explain the meaning of these values \u200b\u200bon the example of specific chemical reactions.
In the chemical thermodynamicase of the active masses binds the equilibrium activity of the starting materials and the reaction products, according to the relation:
Activity. Instead of activity, the monitoring (for the reaction in the ideal solution) can be used, partial pressure (reaction in a mixture of ideal gases), fugitivity (reaction in a mixture of real gases);
Stoichiometric coefficient (for starting materials is adopted negative, for products - positive);
Chemical equilibrium constant. The index "A" here means the use of the value of the formula.
The effectiveness of the reaction is estimated usual, calculating the yield of the reaction product (paragraph 5.11). At the same time, it is also possible to estimate the effectiveness of the reaction, determining which part of the most important (usually the most expensive) substance has become a target reaction product, for example, which part SO 2 has become SO 3 in the production of sulfuric acid, that is, to find the degree of transformationsource substance.
Let a brief scheme of the proceeding reaction
Then the degree of conversion of the substance A in the substance in (A) is determined by the following equation
where n. Ruorag (a) - the amount of substance reagent A, reacted to form a product in, and n. Source (a) - the initial amount of substance reagent A. 
Naturally, the degree of conversion can be expressed not only through the amount of substance, but through any proportional values \u200b\u200bof it: the number of molecules (formula units), mass, volume.
If the reagent A is taken into the disadvantage and losses of the product in one can be neglected, the degree of conversion of the reagent is usually equal to the product output in
Exception - reactions in which the starting material is obviously spent on the formation of several products. So, for example, in the reaction
CL 2 + 2KOH \u003d KCL + KCLO + H 2 O
chlorine (reagent) is equally converted to potassium chloride and potassium hypochlorite. In this reaction, even at a 100% yield of KCLO, the degree of conversion to it chlorine is 50%.
The value known to you is the degree of protolysis (paragraph 12.4) - a special case of the degree of transformation:
In the framework of the TED, similar quantities are called the degree of dissociation Acids or bases (designated as well as the degree of protolysis). The degree of dissociation is associated with a dissociation constant in accordance with the law of dilution of ostelald.
As part of the same theory, the equilibrium of hydrolysis is characterized degree of hydrolysis (h.), while using the following expressions that bind it with the initial concentration of the substance ( from) and dissociation constants of weak acids formed during hydrolysis (K HA) and weak bases ( K. MOH):
The first expression is valid for hydrolysis of salts of weak acid, the second - salts of a weak base, and the third - salts of weak acid and a weak base. All these expressions can only be used for diluted solutions with a degree of hydrolysis of not more than 0.05 (5%).
Typically, the equilibrium yield is determined by the well-known equilibrium constant with which it is associated in each particular case of a certain ratio.
The product output can be changed by shifting the reaction equilibrium in reversible processes, the effects of such factors as temperature, pressure, concentration.
In accordance with the principle of Le Chatelin, the equilibrium degree of conversion increases with an increase in pressure during simple reactions, and otherwise the volume of the reaction mixture does not change and the product output does not depend on pressure.
The effect of temperature on the equilibrium output, as well as on the equilibrium constant, is determined by the sign of the thermal effect of the reaction.
For a more complete estimate of reversible processes, the so-called yield from the theoretical (out of equilibrium) is used, equal to the ratio of the truly obtained product with the amount that would be in a state of equilibrium.
Thermal dissociation is chemical
reactive decomposition reaction substance caused by raising the tempo.
At T. d. Of one substance, several (2H2H + OSAO + CO) or one simpler
Equilibrium T. d. Installed according to the existing masses. It
may be characterized or equilibrium constant, or the degree of dissociation
(The ratio of the number of broken molecules to the total number of molecules). IN
most cases T. D. accompanied by the absorption of heat (increment
entalpy
DN\u003e 0); Therefore, in accordance with Le Charnel, the principle
heating enhances it, the degree of displacement T. d. with temperature is determined
the absolute value of the day. Pressure prevents T. D. The stronger than the bigger
change (increasing) of the number of moles (di) gaseous substances
the degree of dissociation from pressure does not depend. If hard matter is not
form solid solutions and are not in a highly dispersed state,
that is the pressure of T. d. Definitely determined the tempo. To implement T.
d. solid substances (oxides, crystallohydrates, etc.)
it's important to know
temp-RU, when the dissociation pressure becomes equal to external (in particular,
atmospheric) pressure. Since the release gas can overcome
environmental pressure, then upon reaching this tempo, the decomposition process
immediately enhances.
Dependence of the degree of dissociation on temperature: The degree of dissociation increases with increasing temperature (temperature increase leads to an increase in the kinetic energy of dissolved particles, which contributes to the decay of molecules to ions) 
The degree of transformation of the source substances and the equilibrium yield of the product. Methods for their calculation at a given temperature. What data are required for this? Give a calculation scheme for any of these quantitative characteristics of chemical equilibrium on an arbitrary example.
The degree of transformation is the amount of reacted reagent, referred to its initial quantity. For the simplest reaction, where is the concentration at the inlet to the reactor or at the beginning of the periodic process, the concentration at the outlet of the reactor or the current moment of the periodic process. For an arbitrary reaction, for example, 
In accordance with the definition of the calculated formula the same :. If in the reaction several reagents, the degree of transformation can be considered for each of them, for example, for the reaction 
The dependence of the degree of transformation on the reaction time is determined by the change in the concentration of the reagent on time. In the initial moment of time, when nothing turned into, the degree of conversion is zero. Then, as the reagent turns, the degree of turning grows. For an irreversible reaction, when nothing interferes with the reagent to spend completely, its value tends (Fig. 1) to one (100%). 
Fig.1. The greater the reagent spending rate determined by the value of the speed constant, the faster the degree of transformation is growing, which is presented in the figure. If the reaction is reversible, then when the reaction is striving to the equilibrium, the transformation is striving for an equilibrium value, the value of which depends on the ratio of the constants of the speeds of direct and reverse reaction (from the equilibrium constant) (Fig.2). 
Fig.2 The yield of the target product product output is the number of the actually obtained target product, referred to the amount of this product, which would have happened if the entire reagent switched to this product (to the maximum possible amount of product obtained). Or (through the reagent): the amount of reagent actually transferred to the target product, assigned to the initial number of reagent. For the simplest reaction, the output, and having in mind that for this reaction, 
. For the simplest reaction, the output and the degree of transformation is the same value. If the transformation passes with a change in the amount of substances, for example, in accordance with the definition, the stoichiometric coefficient should enter the calculated expression. In accordance with the first definition, the imaginary amount of the product, obtained from the entire initial amount of the reagent, will be two times less for this reaction than the initial amount of reagent, i.e. , I. estimated formula . In accordance with the second definition, the amount of reagent that actually passed into the target product will be twice as much as the product was formed, i.e. , then the calculated formula. Naturally, both expressions are the same. For a more complex reaction, the calculated formulas are recorded in the same way in accordance with the definition, but in this case the output is no longer equal to the degree of transformation. For example, for reaction, 
. If in the reaction several reagents, the output can be calculated for each of them, if more than several target products, then the output can be considered for any target product for any reagent. As can be seen from the structure of the calculated formula (there is a constant value in the denominator), the dependence of the yield from the reaction time is determined by the dependence on the time of the concentration of the target product. So, for example, for reaction 
This dependence looks like in Fig.3. 
Fig. 3.
The degree of transformation as a quantitative characteristic of chemical equilibrium. How to affect the increase in total pressure and temperature on the degree of transformation of the reagent ... in the gas phase reaction: ( the equation is given)? Give the rationale for the answer and the corresponding mathematical expressions.
If external conditions chemical process Do not change, then the condition of chemical equilibrium can persist how long. Changes in the conditions of reaction (temperature, pressure, concentration) can be achieved shift or shift chemical equilibrium in the desired direction.
The balance of equilibrium to the right leads to an increase in the concentration of substances, the formulas of which are located in the right part of the equation. The displacement of equilibrium to the left will lead to an increase in the concentration of substances, the formulas of which are located on the left. In this case, the system will switch to a new equilibrium state characterized by other values \u200b\u200bof equilibrium concentrations of reaction participants.
The displacement of the chemical equilibrium caused by the change in the conditions is subject to the rule formulated in 1884 by the French physicist A. Le Chatelse (the principle of Le Chateel).
Principle Le Chateel: If a system that is in a state of chemical equilibrium has any effect, for example, change the temperature, pressure or concentration of reagents, then the equilibrium will shift in the direction of the reaction that weakens the impact .
The effect of changes in the concentration on the shift of chemical equilibrium.
According to the principle of Le Chatel an increase in the concentration of any of the reaction participants causes an equilibrium displacement towards the reaction, which leads to a decrease in the concentration of this substance.
The effect of concentration on the state of equilibrium is subject to the following rules:
With an increase in the concentration of one of the starting materials, the rate of direct reaction increases and equilibrium is shifted in the direction of formation of reaction products and vice versa;
With an increase in the concentration of one of the reaction products, the rate of reverse reaction increases, which leads to an equilibrium displacement in the direction of the formation of the source substances and vice versa.
For example, if in the equilibrium system:
SO 2 (g) + NO 2 (g) SO 3 (g) + No (g)
increase the concentrations of SO 2 or NO 2, then, in accordance with the law of the active masses, the rate of direct reaction will increase. This will lead to an equilibrium displacement to the right, which causes the spending of starting materials and an increase in the concentration of reaction products. A new state of equilibrium is established with new equilibrium concentrations of starting materials and reaction products. With a decrease in concentration, for example, one of the reaction products, the system will respond in such a way that the concentration of the product increases. The advantage will receive a direct reaction, leading to an increase in the concentration of reaction products.
The effect of changes in pressure on the displacement of chemical equilibrium.
According to the principle of Le Chatel increased pressure leads to a displacement of equilibrium towards the formation of a smaller amount of gaseous particles, i.e. towards smaller volume.
For example, in a reversible reaction:
2NO 2 (g) 2no (g) + o 2 (g)
of 2 Mol NO 2, 2 mol NO and 1 mol o 2 is formed. Stociometric coefficients in front of gaseous substance formulas indicate that the flow of direct reaction leads to an increase in the number of gases, and the flow of reverse reaction, on the contrary, reduces the number of gaseous substance. If there is an external effect on such a system by, for example, by increasing the pressure, the system will respond in such a way that it is impact to weaken. The pressure may decrease if the equilibrium of this reaction is shifted towards a smaller number of a moles of a gaseous substance, which means there are fewer volumes.
On the contrary, the increase in pressure in this system is associated with an equilibrium displacement to the right - towards the decomposition of NO 2, which increases the amount of gaseous substance.
If the number of gaseous substances is before and after the reaction remains per capita, i.e. The volume of the system does not change during the reaction, the change in pressure equally changes the speeds of direct and reverse reactions and does not affect the condition of chemical equilibrium.
For example, in the reaction:
H 2 (g) + Cl 2 (g) 2HCl (g),
the total amount of gaseous substances before and after the reaction remains constant and the pressure in the system does not change. The equilibrium in this system is not shifted when the pressure changes.
Effect of temperature change on chemical equilibrium displacement.
In each reversible reaction, one of the directions corresponds to the exothermic process, and the other is endothermic. So in the ammonia synthesis reaction, the direct reaction is exothermic, and the reverse reaction is endothermic.
N 2 (g) + 3H 2 (g) 2NH 3 (g) + Q (-Δh).
When the temperature changes, speeds of both direct and reverse reactions are changed, however, the change in speeds is not equally degree. In accordance with the Arrhenius equation in more than An endothermic reaction is reacting to a change in temperature, characterized by large meaning Activation energy.
Therefore, it is necessary to know the thermal effect of the process to assess the effect of temperature on the direction of displacement of chemical equilibrium. It can be determined experimentally, for example, using a calorimeter, or calculated on the basis of the Law of Gesse. It should be noted that the temperature change leads to a change in the value of the chemical equilibrium constant (K p).
According to the principle of Le Chatel increase in temperature shifts equilibrium towards the endothermic reaction. When the temperature decreases, the equilibrium shifts in the direction of the exothermic reaction.
In this way, temperature increase In ammonia synthesis reaction will lead to equilibrium displacement toward endothermic reactions, i.e. Left. The advantage is obtained by the reverse reaction flowing with heat absorption.
If the system is in a state of equilibrium, it will remain in it until the external conditions are kept constant. If conditions change, the system will come out of equilibrium - the speed of direct and reverse processes will change unequal - the reaction will flow. Cases of equilibrium impairment are most important due to a change in the concentration of any of the substances involved in equilibrium, pressure or temperature.
Consider each of these cases.
Violation of equilibrium due to a change in the concentration of any of the substances involved in the reaction. Let hydrogen, iodomodorod and a medium pair are in equilibrium with each other at certain temperatures and pressure. We introduce an additional amount of hydrogen into the system. According to the law of the mass, an increase in the concentration of hydrogen will entail an increase in the rate of direct reaction - the synthesis reaction Hi, while the rate of reverse reaction will not change. In the forward direction, the reaction will now flow faster than in the opposite. As a result of this, the concentration of hydrogen and the vapor of the iodine will decrease, which will entail the slowdown in the direct reaction, and the Hi concentration will increase that it will accelerate the reverse reaction. After some time, the speed of direct and reverse reactions, a new equilibrium will be established again. But the concentration of Hi will now be higher than it was before adding, and the concentration is lower.
The process of changing concentrations caused by an imbalance is called a displacement or a balance of equilibrium. If there is an increase in the concentrations of substances in the right part of the equation (and, of course, at the same time a decrease in the concentrations of the substances standing on the left), they say that the balance is shifted to the right, i.e. in the direction of the flow of direct reaction; With reverse change of concentrations, they say the displacement of the equilibrium to the left - in the direction of the reverse reaction. In the considered example, the balance shifted to the right. At the same time, the substance, an increase in the concentration of which caused a malfunction, entered into the reaction - its concentration decreased.
Thus, with an increase in the concentration of any of the substances involved in equilibrium, the equilibrium is shifted towards the consumption of this substance; With a decrease in the concentration of any of the substances, the equilibrium shifts towards the formation of this substance.
Equilibrium disorder due to pressure change (by reducing or increasing the volume of the system). When gases are involved in the reaction, equilibrium can be impaired when the system changes.
Consider the effect of pressure on the reaction between nitrogen monoxide and oxygen:
Let a mixture of gases, and is in chemical equilibrium at a certain temperature and pressure. Without changing the temperatures, increase the pressure so that the system volume decreased by 2 times. At first, partial pressure and concentrations of all gases will increase by half, but the ratio between the speeds of direct and reverse reactions will change - the equilibrium will break.
In fact, the equilibrium values, and, and direct and reverse reaction rates were equal and were determined by the equations of the same to increase the pressure concentration of gases.
At the first moment, after compression, the concentration of gases will be doubled compared with their initial values \u200b\u200band will be equal, respectively, and. At the same time, the speed of direct and reverse reactions will be determined by the equations:
Thus, as a result of an increase in pressure, the speed of direct reaction increased 8 times, and the reverse - only 4 times. Equilibrium in the system will break - direct response will prevail over the reverse. After speed comes, the balance will again be established, but the amount in the system will increase, the equilibrium will shift to the right.
It is easy to see that the unequal change in the speeds of direct and reverse reactions is due to the fact that in the left and in right parts The equations of the reaction under consideration is different number of gases molecules: one oxygen molecule and two nitrogen monoxide molecules (only three gas molecules) are converted into two gas dioxide molecules. Gas pressure is the result of the blows of his molecules about the wall of the vessel; Upcable conditions, the gas pressure is higher than the more molecules are concluded in this volume of gas. Therefore, the reaction flowing with an increase in the number of gases molecules leads to an increase in pressure, and the reaction flowing with a decrease in the number of gases molecules is to reduce it.
Remembering this, the conclusion about the effect of pressure on chemical equilibrium can be formulated as follows:
With an increase in pressure by compressing the system, the equilibrium shifts towards a decrease in the number of gases molecules, i.e., in the direction of the pressure drop, with a decrease in pressure, the equilibrium shifts towards the increase in the number of gases molecules, i.e. towards increasing pressure.
In the case when the reaction proceeds without changing the number of gases molecules, the equilibrium is not violated during compression or when the system is expanded. For example, in the system
equilibrium is not violated when the volume changes; Hi output does not depend on pressure.
Equilibrium disorder due to temperature change. The equilibrium of the overwhelming majority of chemical reactions is shifted when temperatures change. A factor that determines the direction of the balance of equilibrium is the sign of the thermal effect of the reaction. It can be shown that with an increase in temperature, the equilibrium is shifted in the direction of endothermic, and with a decrease in the direction of the exothermic reaction.
So, ammonia synthesis is an exothermic reaction
Therefore, with an increase in temperature, the equilibrium in the system is shifted to the left - in the direction of the decomposition of ammonia, since this process comes with heat absorption.
On the contrary, the synthesis of nitrogen oxide (II) is an endothermic reaction:
Therefore, with an increase in temperature, the equilibrium in the system is shifted to the right - towards education.
Patterns that manifest themselves in the considered examples of a chemical equilibrium impairment represent private cases common principledefining influence various factors on equilibrium systems. This principle, known as the principle of Le Chateel, can be formulated as follows:
If the system in equilibrium is to have any impact, then the equilibrium will be shown in this direction in this direction that the impact has decreased.
Indeed, when introduced into the system of one of the substances involved in the reaction, the equilibrium is shifted towards this substance. "With an increase in pressure, it shifts so that the pressure in the system is reduced; with increasing temperature, the equilibrium shifts towards the endothermic reaction - the temperature in the system falls.
The principle of Le Chatelus applies not only to chemical, but also on various physico-chemical equilibrium. Displacement of equilibrium when changing the conditions of such processes such as boiling, crystallization, drescent, occurs in accordance with the principle of Le Chateel.
Chemical equilibrium and principles of its displacement (principle of Le Chateel)
In reversible reactions under certain conditions, a condition of chemical equilibrium may occur. This condition at which the rate of reverse reaction becomes equal to the rate of direct reaction. But in order to move the equilibrium in one direction or another, you need to change the conditions for the reaction. The principle of the balance of equilibrium is the principle of Le Chatel.
Basic provisions:
1. External influence The system in a state of equilibrium leads to a displacement of this equilibrium in the direction in which the effect of the impact is weakened.
2. With an increase in the concentration of one of the reacting substances, the equilibrium is shifted towards the consumption of this substance, with a decrease in the concentration of the equilibrium shifts towards the formation of this substance.
3. With an increase in pressure, the equilibrium shifts towards reducing the number of gaseous substances, that is, in the direction of pressure reduction; With a decrease in pressure, the equilibrium shifts towards the increase in the amounts of gaseous substances, that is, in the direction of the pressure increase. If the reaction proceeds without changing the number of molecules of gaseous substances, the pressure does not affect the equilibrium position in this system.
4. With an increase in temperature, the equilibrium shifts towards the endothermic reaction, with a decrease in temperature - towards the exothermic reaction.
For the principles, thank the allowance for "Beginning of Chemistry" Kuzmenko N.E., Eremin V.V., Popkov V.A.
The tasks of the exam on chemical equilibrium (previously A21)
Task number 1.
H2s (g) ↔ h2 (g) + s (g) - q
1. Increased pressure
2. Raising temperature
3. Reducing pressure
Explanation: To begin with, consider the reaction: all substances are gases and in the right part two product molecules, and in the left only one, the reaction is endothermic (-Q). Therefore, we consider the change in pressure and temperature. We need equilibrium to shift towards the reaction products. If we enhance the pressure, then the balance will shift towards a decrease in volume, that is, towards reagents - it does not fit us. If we increase the temperature, the balance will shift towards the endothermic reaction, in our case, in the direction of the products, which was required. The correct answer is 2.
Task number 2.
Chemical equilibrium in the system
SO3 (g) + NO (g) ↔ SO2 (g) + NO2 (g) - q
it will shift towards the formation of reagents at:
1. Increase the concentration of NO
2. Increase the concentration of SO2
3. Increases temperature
4. Increase pressure
Explanation: All gase substances, but the volumes in the right and left parts of the equation are the same, so the pressure on the equilibrium in the system will not affect the system. Consider the temperature change: with an increase in temperature, the equilibrium shifts towards the endothermic reaction, just towards reagents. The correct answer is 3.
Task number 3.
In system
2nO2 (g) ↔ N2O4 (g) + Q
equilibrium to the left will contribute to the left
1. Increased pressure
2. Increased concentration of N2O4
3. Decrease in temperature
4. Introduction of the catalyst
Explanation: We draw attention to the fact that the volume of gaseous substances in the right and left parts of the equation are not equal, so the change in the pressure will affect the equilibrium in this system. Namely, with an increase in pressure, the equilibrium shifts towards reducing the number of gaseous substances, that is, right. It does not fit us. The reaction is exothermic, therefore, the change in temperature will affect the equilibrium of the system. When the temperature decreases, the equilibrium will be shifted towards the exothermic reaction, that is, also right. With an increase in the concentration of N2O4, the equilibrium shifts towards this substance, that is, to the left. The correct answer is 2.
Task number 4.
In the reaction
2fe (T) + 3H2O (g) ↔ 2Fe2O3 (T) + 3N2 (g) - Q
equilibrium will shift towards the reaction products at
1. Increased pressure
2. Addition of the catalyst
3. Appendix of iron
4. Water adding
Explanation: The number of molecules in the right and left parts is the same, so that the change in pressure to influence the equilibrium in this system will not be. Consider an increase in the concentration of iron - the balance should shift towards this substance, that is, to the right (in the direction of the reaction products). The correct answer is 3.
Task number 5.
Chemical equilibrium
H2O (g) + C (T) ↔ H2 (g) + CO (g) - Q
will shift towards the formation of products in case
1. Increased pressure
2. Increases temperature
3. Increase process time
4. Applications of catalyst
Explanation: The change in pressure will not affect the equilibrium in this system, since not all substances are gaseous. With an increase in temperature, 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.
With the increase in pressure, the chemical equilibrium will shift towards the products in the system:
1. CH4 (D) + 3S (T) ↔ 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: At the reaction 1 and 4, the pressure change does not affect, therefore not all participating agents of gaseous ones, in equation 2 in the right and left parts of the number of molecules equally, so that pressure will not affect. Equation is remained 3. Check: with an increase in pressure, the equilibrium should shift towards the decrease in the amounts of gaseous substances (right 4 molecules, left 2 molecules), that is, in the direction of the reaction products. The correct answer is 3.
Task number 7.
Does not affect equilibrium displacement
H2 (g) + i2 (g) ↔ 2hi (g) - q
1. Increased pressure and add catalyst
2. Increases temperature and adding hydrogen
3. Reducing the temperature and addition of iodorodor
4. Adding iodine and adding hydrogen
Explanation: In the right and left parts of the number of gaseous substances are the same, so the change in pressure to influence the equilibrium in the system will not, will also not affect the addition of the catalyst, because as soon as we add the catalyst to accelerate a direct reaction, and then immediately reverse and equilibrium in the system will restore . The correct answer is 1.
Task number 8.
To shift to the right equilibrium in the reaction
2no (g) + o2 (g) ↔ 2nO2 (g); Δh °<0
required
1. Introduction of the catalyst
2. Decrease in temperature
3. Lowering pressure
4. decrease in oxygen concentration
Explanation: The decrease in oxygen concentration will lead to an equilibrium displacement towards reagents (left). The decrease in pressure will move the balance towards the decrease in the number of gaseous substances, that is, right. The correct answer is 3.
Task number 9.
Product yield in exothermic reaction
2NO (g) + O2 (g) ↔ 2nO2 (g)
with the simultaneous increase in temperature and lowering pressure
1. Increase
2. Decrease
3. Will not change
4. First increase, then decrease
Explanation: When the temperature is raised, the equilibrium shifts towards the endothermic reaction, that is, in the direction of products, and when the pressure decreases, the equilibrium shifts towards an increase in the amounts of gaseous substances, that is, too, to the left. Therefore, the product output will decrease. The correct answer is 2.
Task number 10.
Increase the release of methanol in the reaction
CO + 2N2 ↔ CH3OH + Q
promotes
1. Increase temperature
2. Introduction of the catalyst
3. Introduction inhibitor
4. Increased pressure
Explanation: With an increase in pressure, the equilibrium is shifted towards the endothermic reaction, that is, towards reagents. The increase in pressure shifts the balance towards the decrease in the amounts of gaseous substances, that is, in the direction of the formation of methanol. The correct answer is 4.
Tasks for an independent decision (Answers at the bottom)
1. In the system
Co (g) + H2O (g) ↔ CO2 (g) + H2 (g) + Q.
the displacement of chemical equilibrium in the direction of the reaction products will contribute
1. Reducing pressure
2. Increase temperature
3. Increased carbon monoxide concentration
4. Increased hydrogen concentration
2. In which system, with an increase in pressure, the balance is shifted towards the reaction products
1. 2CO2 (g) ↔ 2So (g) + o2 (g)
2. C2N4 (g) ↔ C2N2 (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. Increased pressure
2. Raising temperature
3. Reducing pressure
4. Use catalyst
4. Chemical equilibrium in the system
C2N5on + CH3Cone ↔ CH3CO2N5 + H2O + Q.
shifts in the direction of the reaction products when
1. Addition of water
2. Reducing acetic concentration
3. Enlarge 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 when
1. Increased pressure
2. Raising temperature
3. Reducing pressure
4. Application of catalyst
6. Chemical equilibrium in the system
CO2 (g) + C (TV) ↔ 2So (g) - q
will shift towards the reaction products at
1. Increased pressure
2. Decrease the temperature
3. Enhance the concentration of
4. Raising temperature
7. Changing pressure will not affect the condition 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 an increase in pressure, the chemical equilibrium will shift towards the starting materials?
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
C4N10 (g) ↔ C4N6 (g) + 2N2 (g) - Q
will shift towards the reaction products at
1. Raising temperature
2. Decrease the temperature
3. Use catalyst
4. Reducing the concentration of Bhutan
10. On the condition of chemical equilibrium in the system
H2 (g) + i2 (g) ↔ 2hi (g) -q
does not affect
1. Increased pressure
2. Increased iodine concentration
3. Increase temperature
4. Decrease in temperature
Tasks 2016
1. Set the correspondence between the equation of the chemical reaction and the displacement of the chemical equilibrium with increasing pressure in the system.
Reaction Equation Displacement Chemical Equilibrium
A) n2 (g) + o2 (g) ↔ 2no (g) - q 1. shifts towards a direct reaction
B) N2O4 (g) ↔ 2nO2 (g) - Q 2. shifts towards the reverse reaction
C) CaCO3 (TV) ↔ Cao (TV) + CO2 (g) - Q 3. Does not be dismissed equilibrium
D) FE3O4 (TV) + 4CO (g) ↔ 3Fe (TV) + 4CO2 (g) + q
2. Set the correspondence between the external influence on the system:
CO2 (g) + C (TV) ↔ 2So (g) - q
and the shift of chemical equilibrium.
A. Increased concentration of CO 1. shifts towards a direct reaction
B. Reduction of pressure 3. The equilibrium displacement does not occur.
3. Install the correspondence between the external influence on the system
Nson (g) + s5n5on (g) ↔ NSOOS2N5 (g) + H2O (g) + q
External impact of chemical equilibrium displacement
A. Adding Nson 1. shifts towards a direct reaction
B. Water dilution 3. There is no equilibrium displacement
G. Raising Temperature
4. Install the correspondence between the external influence on the system
2no (g) + o2 (g) ↔ 2nO2 (g) + q
and displacement of chemical equilibrium.
External impact of chemical equilibrium displacement
A. Reducing pressure 1. shifts towards a direct reaction
B. Increase temperature 2. shifts towards the reverse reaction
B. Increase the temperature NO2 3. The equilibrium displacement does not
Additional O2.
5. Set the correspondence between the external influence on the system
4NH3 (g) + 3O2 (g) ↔ 2n2 (g) + 6H2O (g) + Q
and displacement of chemical equilibrium.
External impact of chemical equilibrium displacement
A. Decreased temperature 1. Offset towards a direct reaction
B. Increased pressure 2. shifts towards the reverse reaction
B. Increased concentration in ammonia 3. No equilibrium displacement occurs
G. Removing Water Vapor
6. Install the correspondence between the external influence on the system
WO3 (TV) + 3H2 (g) ↔ W (TV) + 3H2O (g) + Q
and displacement of chemical equilibrium.
External impact of chemical equilibrium displacement
A. Increased temperature 1. shifts towards a direct reaction
B. Increased pressure 2. shifts towards the reverse reaction
B. Using catalyst 3. No balance displacement
G. Removing Water Vapor
7. Install the correspondence between the external influence on the system
C4N8 (g) + H2 (g) ↔ C4N10 (g) + Q
and displacement of chemical equilibrium.
External impact of chemical equilibrium displacement
A. Increased hydrogen concentration 1. shifts towards a direct reaction
B. Raising temperature 2. shifts towards the reverse reaction
B. Increased pressure 3. There is no equilibrium displacement
Using catalyst
8. Install the correspondence between the chemical reaction equation and the simultaneous change in the system parameters leading to the displacement of chemical equilibrium towards the direct reaction.
Reaction equation Change system parameters
A. H2 (g) + F2 (g) ↔ 2HF (g) + Q 1. Increase the temperature and concentration of hydrogen
B. H2 (D) + I2 (TV) ↔ 2HI (g) -q 2. Reducing the temperature and concentration of hydrogen
V. CO (D) + H2O (g) ↔ CO2 (g) + H2 (g) + Q 3. Increase the temperature and decrease in hydrogen concentration
C4H10 (g) ↔ C4H6 (g) + 2H2 (g) -q 4. Reducing the temperature and an increase in hydrogen concentration
9. Install the correspondence between the chemical reaction equation and the displacement of chemical equilibrium with an increase in the pressure in the system.
Reaction equation Direction of chemical equilibrium displacement
A. 2HI (g) ↔ H2 (g) + i2 (TV) 1. shifts towards a direct reaction
B. C (g) + 2s (g) ↔ CS2 (D) 2. shifts towards the reverse reaction
B. C3H6 (D) + H2 (g) ↔ C3H8 (D) 3. No equilibrium displacement
G2 (g) + F2 (g) ↔ 2HF (g)
10. Install the correspondence between the chemical reaction equation and the simultaneous change in the conditions of its conduct leading to the displacement of the chemical equilibrium towards the direct reaction.
Reaction equation Change conditions
A. N2 (g) + h2 (g) ↔ 2NH3 (g) + Q 1. Increase temperature and pressure
B. N2O4 (g) ↔ 2nO2 (g) -q 2. Decrease of temperature and pressure
V. CO2 (g) + C (TV) ↔ 2CO (g) + Q 3. Increase temperature and pressure reduction
G. 4HCl (g) + O2 (g) ↔ 2H2O (g) + 2Cl2 (g) + Q 4. Reducing 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 tasks We thank the collections of exercises for 2016, 2015, 2014, 2013. Authors:
Kavernina A.A., Dobrotina D.Yu., Snastina M.G., Savinkina E.V., Vynesova O.G.
