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1、高中化学等效平衡（High school chemistry equivalent balance）High school chemistry equivalent balance.Txt if you love several people at the same time, you are young; if you love only one person, then you are old; if you do not love anyone, you have been reborn. A positive person must have a habit of persistenc
2、e. College entrance examination, poetry appreciation, equivalent balance, default classification, 2010-09-11, 17:51:54 reading, 4 reviews, 0 types: large and medium subscriptionsDialysis of equivalent equilibrium knowledge points and its applicationI. establishment of equivalent balance principlePoi
3、nted out that the chemical equilibrium theory: a reversible reaction, when the external conditions, whether it is from the beginning of Affirmative reaction, or from the reverse reaction, or from the forward and the reverse reactions begin at the same time, finally can reach the equilibrium state. T
4、he state of chemical equilibrium relates to the conditions, but not to the path to balance. Therefore, we put in certain conditions (constant temperature, constant voltage or constant temperature, constant volume), just starting material to join the same reversible reaction different after equilibri
5、um, the reaction mixture of any component fraction (the same volume, quality, amount of substance) are equal, so called each equivalent chemical equilibrium balance.Two, the conditions and types of equivalent equilibrium establishmentAccording to the conditions of establishing equivalent equilibrium
6、, it can be divided into two categories: constant temperature, constant pressure and constant temperature, constant volume. In the constant temperature and constant volume, we must consider two cases of equal and unequal gas molecular number before and after the reaction. The conclusion is: two cate
7、gories and three cases. Their classification, establishment conditions and characteristics are summarized as follows:Explanation: for the reversible reaction of gas molecules with equal number of molecules before and after the reaction, the change of pressure in the constant temperature and constant
8、 volume condition does not affect the movement of the equilibrium.1, constant temperature constant volume (fixed T, V) equivalent balance(1) in T, V conditions, to change the gas volume before and after the reaction the reaction: if the change of initial join, as long as the stoichiometric number of
9、 reversible reaction than converted into balance on both sides of the same side of the same amount of substance and the original balance is two equivalent balance.(2) under the condition of definite T and V, the reaction of the volume of the gas before and after the reaction is invariable: if the ra
10、tio of the amount of the reactants (or the products) is the same as the original equilibrium, two, the balance is equivalent.2, constant temperature constant pressure (T, P) equivalent balanceIn T, under the condition of P: if the change of initial join, as long as the stoichiometric number of rever
11、sible reaction than converted into the left and right sides of the same side of the equation of material molar ratio and the original balance is the same, two equivalent balance.Namely: the reversible reaction gas volume changes before and after the reaction, the constant volume vessel to reach a st
12、ate of equilibrium, the feeding amount must be the same; constant pressure vessel to reach a state of equilibrium, the feeding amount can be different, but the investment proportion of the same. For the reversible reaction of gas volume before and after the reaction, whether in constant volume conta
13、iner or constant pressure change, in order to achieve the same equilibrium state, as long as the proportion of material can be fed. See the following table for details:Table 1 Classification of equivalent balance, establishment conditions and resultsreactionconditionClassified constant temperature,
14、constant volume, constant temperature and constant pressureThe number of gas molecules is unequal before and after the reactionA (g) +B (g) C (g) has equal molecular numbers before and after the reactionA (g) +B (g) 2 C (g) reversible reactions of all gasesClassification I II IIIThe establishment of
15、 conditions of products according to the measurement of equivalent balance coefficient of the reversible reaction equation of all push down as the reactant, the initial of the same material with two balance established by the same security amount two cases, equivalent. (this is essentially the same
16、product according to the stoichiometric balance) reversible reaction equation of all push count as reactants, two equilibrium equivalent molar ratio is the same in the two situations when the. (such as the reaction under second conditions: molar ratio is n times the material reaction the first case
17、of the ratio of the product) according to the measurement of the reversible reaction equation of the coefficient of push down as reactants, two equilibrium molar ratio is the same in the two under the condition of the establishment of the equivalent. (for example, the ratio of the amount of reactant
18、s in the second case is n times the amount of reactants in the first case)The results of the two balance components n, C, 100 components are the same: the density of gas two times balance is the same, the same substance as the reaction rate V. Two equilibrium components of 100 N, C with the same com
19、ponent, the proportion of gas density change: two equilibrium is not necessarily the same reaction rate V of same material is not the same. In the two equilibrium, the components of each component are the same as the C, and the N varies in proportion. When the two balance occurs, the density of the
20、gas is the same as that of P, and the reaction rate of the same substance is the same as that of V.Note: the equivalent balance formula can be summarized as follows: the pressure ratio is the same;Equal capacity: if the coefficient (gas coefficient) unchanged, can be the same as the ratio.Three. The
21、 application of equivalent balance in solving chemical equilibrium questions1. The amount of matter in different starting statesExample 1. If the temperature is constant, adding 2molSO2, 1mo1O2 in a constant volume container, the following reactions occur:2SO2 (g) +O2 (g), if equilibrium, the amount
22、 of substance SO3 is aMo1/L. If the material is changed at the beginning, and the quantity of the substance SO2 is expressed by a; the B represents the amount of the substance of O2; the C indicates the amount of the substance in SO3; however, the amount of substance SO3 in equilibrium is required t
23、o be aMo1/L, fill in the blanks below:(1) if a=0, b=0, then c=; (2) if a=0.5, then b=, c=;(3) write the relation that a, B, C should satisfy (please use the two equation representation, one containing only a and C and the other containing only B and C):,.Analysis: according to the constant temperatu
24、re and volume equivalent balance conditions, meets the equation in measurement data is converted into SO2 and O2 of the amount of substance and the original start adding SO2 and O2 is equal to the amount of material. Therefore, a+c=2,2b+c=2 should be satisfied and thus available (1) in c=2, (2) b=0.
25、25, c=1.5.thinking if the volume fixed container in the above problem is changed into a pressure invariant container, the same answer to the above question (third small questions, parentheses, text, removal), then what is the situation? (reference answer: C 0; b = 0.25, C = 0; a:b = 2:1, C = 0 or a
26、= b = 0, C 0)2, the judgment of equivalent balanceExample 2. in a constant temperature and constant pressure vessel, the A and B gases can establish the following equilibrium: 2A (g) +2B (g)C (g) +3D (g) is now balanced from two paths: I. the starting quantities of.A and B are 2mo1; the initial quan
27、tities of II,.C and D are 2mo1 and 6mo1, respectively. The following statements are true: ()When the A, I and II two pathways finally reach equilibrium, the composition of the mixture gas in the system is the sameWhen the B, I and II two pathways finally reach equilibrium, the percent composition of
28、 the mixed gases in the system is differentWhen C reaches equilibrium, the average relative molecular mass of the mixture gas is the same as that of pathway 1 and pathway IIWhen D reaches equilibrium, the gas density of pathway I is 1/2 of pathway IIAnalysis: the establishment of chemical equilibriu
29、m has nothing to do with the reaction path. It can be equal to the initial amount of A and B to be 4mo1 (the extreme transformation is carried out, and the complete reaction of 2mo1 and 6mo1D is converted into 4mo1A, 4mo1B).Join 2mo1A 2mo1B, volume VL, constant temperature and pressure, then add 2mo
30、1A and 2mo1B volume is changed to 2VL, A, B visible, the initial amount of 4mo1 is equivalent to two A, the initial B was 2mo1 under the same conditions of superposition, balance, concentration of the same objects of the same the same, conversion rate, average molar mass and density are the same. So
31、 choose the A and C options.3. Judgment of moving direction of chemical balanceExample 3. at a certain temperature, in a variable volume container, react with 2A (g) +2B (g)When 2C (g) reaches equilibrium, the contents of A, B and C are 4mo1, 2mo1 and 4mo1, respectively. Keep the temperature and pre
32、ssure constant,The amount of substance in the three of the equilibrium mixture is adjusted as follows)A. were halved, B. doubling, C. increased, 1mo1 and D. decreased by 1mo1Analysis: under isothermal and isobaric conditions, the material according to the stoichiometric reaction equation number into
33、 a reactant or product, the molar ratio is consistent with the equivalent balance ratio of the three options A, B for 2:1:2, and in the same proportion, equivalent balance, balance does not move. C can be expected to be added in the two step, adding 1molA, 0.5mo1B, 1mo1C for the first time, when the
34、 balance does not move, second times before the addition of 0.5mo1B (the one-time add 1mo1 and equivalent), increased the concentration of reactants, balance. D is reduced by 1, can also be envisaged as the two step: first reduce 1mol, A, B, reduce 0.5mo1, C, reduce 1mo1, at this time balance does n
35、ot move. B is now reduced by 0.5mo1, reducing reactant concentration and balancing left shift. The answer is the C option.4. The conversion rate (or volume fraction) of a substance when the same reaction begins at different equilibrium statesExample 4. in the same volume of a, B and two containers,
36、a is equipped with SO2 and O2 each 1g, B is equipped with SO2 and O2, each 2G, at the same temperature reaction: 2, SO2+O2 2SO3, and achieve balance. In this process, if the conversion rate of SO2 in a vessel is p%, the conversion rate of SO2 in the container BA, equal to p% B, greater than p% C, le
37、ss than p% D, can not be determinedThis problem is much simpler if the applied process hypothesis and the equivalent equilibrium principle are applied,The process of change is assumed as shown in the following figure:Equilibrium 1 and equilibrium 2 are equivalent equilibrium, and the content and con
38、version rate of each substance are equal. Balance 2The balance 3 is the pressurization process, the balance moves to the right, and the content and the conversion rate of each substance increase, that is to say, the conversion rate of SO2 in the container is greater than p%, so the B option is selec
39、ted.5, the comprehensive application of equivalent balance knowledgeExample 5.I. under constant temperature and constant pressure, the following reaction occurs in a variable volume vessel, A (gas), +B (gas), C (gas)(1) if the 1mo1, A, and 1mo1 B are added to the balance at the start, the a mo1 C is
40、 generated, and the amount of the substance in the A is mo1.(2) if the 3 mo1 A and the 3mo1 B are added at the beginning, when the equilibrium is reached, the amount of the substance that produces C is mo1.(3) if the xmolA, 2mol, B and 1 mo1 C are added at the beginning, when the equilibrium is reac
41、hed, the amount of A and C is y, mo1 and 3amo1, then x=, mo1, and y=Mo1. The average B, the amount of substance (an optional number). The reason for this judgment is that.(a) greater than 2mo1 (b) equal to 2mo1 (c) less than 2mo1 (d) may be greater than or equal to or less than 2mo1.(4) if the re-en
42、try of a 3 mo1 C in a (3) equilibrium mixture, when the equilibrium is reached again, the amount of substance in the C is.If the temperature remains constant, the reaction occurs in a container of the same volume and volume fixed before the reaction (1).(5) start by adding 1 mo1 A and 1 mo1 B to B m
43、o1 C after the balance arrives.B and a (1): the comparison (optional a number). (a) a b (c) a = B (Ding) can not compare the size of a and B; the reason for this judgment is that.Analysis: this title is designed to meet the conditions, the classification of equivalent balance III, (1) can be calcula
44、ted directly for the amount of substance A (1-A) mo1; (2) the A, B of the amount of substance (1) is three times of A, the amount of B material, C generation the amount of substance should be three times that of 3AMo1; as a result of (3) the reaction is balanced, the amount of substance C is 3 a mo1
45、, so it is equivalent to the initial accession of A and B, each 3mo1 should be (x+1=3) x is 2; in equilibrium, the amount of substance in A is three times as much as (1). That is, 3 (1-A). The amount of substance in B depends on the amount of substance C in equilibrium, the amount of 3A mo1 and the
46、amount of substance initially added to C 1Mo1 relationship. (4) the balance established under the conditions is equivalent to (1), so the amount of substance in C is equal to (1), a/ (2-A).Answer: (1) (1-A), (2) 3a, (3) 2, 3-3, a, Ding, if 3A 1, the quantity of B is less than 2 mo1; if 3a=1, the amo
47、unt of B is equal to 2Mo1; if 3A B.0 | share: reading (4) | comments (0) | references (0) | ReportI have an appointment with the princeThe history of todays poetry appreciation in the college entrance examinationI have an appointment with the prince, 2008-09-11 13:23:46 related articlesRecent reader