A few questions about high school chemistry Everybody help me

ch3-ch2-ch2-ch2-ch3.

h is the positive price.

H rarely has negative monovalent, only in sodium hydride, etc.

SO2 overdose.

NH3 overdose.

The concentration range of concentrated sulfuric acid is in the textbook.

io3- +5i- +5ch3cooh =5ch3c00- +3i2 +3h2o;

Conservation according to valence.

It is a white precipitate.

ph3>sh2>hcl;

This follows the principle that the oxidation of the element is strong, and the reduction of cyanide is weak;

It may be ammonia sulfite, or it may be ammonium bisulfite, depending on which is the excess, the former is an excess of ammonia monohydrate, and the latter is an excess of sulfur dioxide.

2. N-pentane, ch3ch2ch2ch2ch3, opens all chemical bonds.

3. The valency of h is +1

4、 +so2 = nh4hso3

SO2 = (NH4)2SO3 + H2O5, generally more than 10mol L is called a concentrated solution, almost 50%.

6、io3^- 5i^- 6ch3cooh = 6ch3coo^- 3i2 + 3h2o

7. Baso3 is a white insoluble precipitate in water, but soluble in hydrochloric acid.

8. CH3OH + H2O = CO2 + 3H29, reduction, PH3 > H2S > HCl is the ability to lose electrons, the element is easy to obtain electrons, that is, the oxidation of the element is weak, and the corresponding silver ion is not easy to lose electrons, that is, the reduction is weak.

So, the oxidation of the element, Cl2 > S > P, So, the reduction, HC< H2S < pH3

Wow Ka Ka I feel so sad, I was so good at chemistry in high school, and now I forget it cleanly, oh my God!!

1.(Select) The following statements about alkanes are false: c

In the alkane molecule, all the chemical bonds are single bond --- pairs, C-C single bond and C-H single bond.

b All alkanes have substitution reactions with Cl2 (chlorine) under light conditions--- photohalogen substitution is a characteristic reaction of alkanes.

The general formula of the C alkane molecule is CNH2N+2, which is not necessarily the --- of alkanes, but the alkanes.

With the increase of the number of carbon atoms, the melting and boiling point of alkanes gradually increases--- pairs, and the number of c atoms increases, the molecular weight increases, and the melting and boiling point increases.

2.Should concentrated HCl be heated for the reaction with mnO2 (chlorine production)? --To heat.

A correct alkane is a saturated hydrocarbon, and all bonds are saturated single bonds.

b Correct substitution reaction is a characteristic reaction of alkanes.

C False The general formula of the alkane molecule is CNH2N+2, and it must be an alkane that conforms to this general formula.

d error. The boiling point cannot be said together.

For the boiling point, the more branched chains, the greater the molecular distance due to steric hindrance, the weak intermolecular force, the low boiling point, and the small density;

However, for the same number of branches, the more symmetrical the molecules, the tighter the molecular binding, the stronger the intermolecular force, the higher the boiling point and the higher the density. For the melting point, the more symmetrical the branched chain, the tighter the molecular bonding, the stronger the intermolecular force, the higher the boiling point, and the higher the density. Want.

1b only reacts with the gas alkane light.

2 Heat.

1 Option C I believe that no one can give a counterexample Isoalkanes are also alkanes.

2 Heating is required.

1 Choose c, because the carbon atom is already in the tetravalent saturation structure at this time, and it is impossible to form other functional groups.

2 Heating is required, which is not a question of how fast or slow the reaction is, but of the reaction mechanism.

1 should be choose B, I did it by the elimination method, the melting point of n-alkanes, the same series C1-C3 is not so regular, but C4 above is increased with the increase of the number of carbon atoms. To be heated.

4HCl (concentrated) + MNO2 === heating ===MnCl2 + Cl2 +2H2O

4HCl (concentrated) + MNO2 === heating ===MnCl2 + Cl2 +2H2O

146 87g

x solution gives x=

After dilution to 100 ml of the amount of Cl- in the solution, the amount of the substance is:

100*37%* = 1mol

Remove 10ml containing the mass of the resulting precipitate.

Cl2 is a small amount of Cl2 + 2i- === i2 + 2cl-

Cl2 overdose 3Cl2 + 2Fe2+ +4i- === 2Fe3+ +2i2 + 6Cl-

Cl2 is a small amount of Cl2 + 2Fe2+ === 2Fe3+ +2Cl-

Cl2 overdose 3Cl2 + 2Fe2+ +4BR- === 2Fe3+ +2BR2 + 6Cl-

If you still have questions, please contact me to discuss them in detail.

a. Error.

Calcium carbide often contains sulfide and phosphide impurities, which react with water to produce H2S and pH3, and can also make acidic KMno4 fade, so it is not certain that acetylene is formed.

b. Error. When heated, ethanol volatilizes, and the ethanol is oxidized to acetic acid by KMNO4, which can also fade KMNO4. Therefore, it is not certain that ethylene has been generated. If an acidic KMno4 solution is used, the gas should be introduced into the water to eliminate the interference of ethanol.

c. Correct. None of the impurities can discolor bromine water, and the resulting ethylene is the only substance that can discolor bromine water. It can be confirmed that ethylene has been produced. Because ethanol does not discolor bromine water.

d error. When bromine vapor is introduced into the Agno3 solution, there is also a yellowish precipitate Agbr. Select C

n2+3h2=2nh3。This is the reaction equation. If the number of reaction meters is increased at the same time, the conversion rate remains the same.

If there is no number of measurements by reaction. Then it depends on which one increases faster, and the corresponding conversion rate is lower, and the other is higher... The time is coming soon, ask the landlord to adopt it first.

Explain again.

The first question, this question, is possible, so you can use the limit approach method, assuming that ammonia and hydrochloric acid are infinitely close, due to the hydrolysis of ammonia, it may lead to this result: the second question, your method is not applicable, but you should first calculate the flat correlation coefficient k of this reaction, and then use the q calculated for the second time, for comparison, I think you should be able to: the third question, to be solved by the master.

Hope it helps.

Question 3: After pressurization, there may be gases that turn into liquids or even solids, changes the concentration of substances that change their state, change the chemical equilibrium constant, and move the equilibrium.

1.The answer is wrong, it should be a lack of ammonia

Add excess acid to the Naalo2 solution and the ionic equation is.

AlO2- 4H+ Al3+ 2H2O add a small amount of acid to the Naalo2 solution, the ionic equation is.

AlO2- H+ H2O Al(OH)3 state nucleus.

CO2 leakage and merger: CO2 + 2alo2- +3H2O ==2Al(OH)3 (precipitation) +CO3 2-

CO2 excess trace: CO2 + AlO2- +2H2O ==Al(OH)3 (precipitation) +HCO3

First, it's alo-

Second, alo- 4H+ Al3+ 2H2O [excess acid].

Three moles, we see a carboxyl group, an ester group, a carboxyl group consumes a sodium hydroxide, and an ester group consumes a sodium hydroxide, but the hydroxyl group generated is attached to the benzene ring, which is similar to phenol, and the hydroxyl group on the phenol also consumes a sodium hydroxide, so the ester group attached to the benzene ring consumes two moles of sodium hydroxide, which adds up to three moles.

3mol Analysis].

The reaction of aspirin and sodium hydroxide is mainly two-fold:

1. The reaction of -Cooh and Naoh, the amount ratio of the reactive substance is 1:12, and the reaction of -O-C=O and NaOH is hydrolyzed, and the amount ratio of the reactive substance is 1:2ich3

r-o-co-ch3+2naoh---r-ona+ch3coona+h2o

The essence of the reaction is the hydrolysis of R-O-Co-CH3 to produce phenol and acetic acid, which in turn react with NaOH.

So, the last 1mol of aspirin consumes NaOH 3mol satisfactorily

There are 2 reactions between aspirin and sodium hydroxide, the first is acid-base neutralization, and the second is hydrolysis.

The neutralization reaction is the reaction of -COOH and NaOH with a ratio of 1:1 for the amount of reactive substances, and the hydrolysis reaction of R-O-Co-CH3 + 2NaOH --- R-ONA + CH3CoOn + H2O with a ratio of 1:2 for the amount of reactive substances

Because it is a sufficient amount of reaction, the consumption of sodium hydroxide is 3mol

1. Evaporation crystallization and evaporation are not the same concept, evaporation crystallization separates substances whose solubility does not change much with temperature, cooling crystallization is the separation of substances whose solubility changes greatly with temperature, and one is still dissolved and one has been precipitated, and recrystallization is to improve the purity of the substance and make the yield higher.

2 soluble in dilute nitric acid refers to the reaction with dilute nitric acid, soluble in water is dissolved or reacted with water, dilute nitric acid has oxidation, while dilute hydrochloric acid does not.

3Fe2+ is light green, Fe3 is brownish yellow, and Cu2+ is light blue.

4Dialysis is to separate the colloid from the solution, the solution can pass through the semi-permeable membrane, but the solution cannot, salting out is to add a salt solution to precipitate the protein.

5 It depends on whether it is solid-liquid, liquid-liquid, or gas-gas separation, and it also depends on the nature of the separated substance, which is difficult to say.

1. Not a concept, evaporation does not have to crystallize.

Evaporation crystallization is to remove the water in the solution to saturate the solution and precipitate the solute, and cool the crystalline stone to directly reduce the solubility of the solute and make it precipitate. Solid and liquid states are generally separated.

Recrystallization refers to the dissolution of the resulting solute and then crystallization to improve the purity of the separated solute.

2. It is dissolved in dilute nitric acid, which generally refers to the reaction with dilute nitric acid. The difference between dilute nitric acid and dilute hydrochloric acid is that dilute nitric acid is highly oxidizing.

3. Generally, green, light yellow, blue, and transition ions vary greatly in color, but it is not easy to determine.

4. Dialysis refers to the separation of colloids from solutes in solution, and semi-permeable membranes are used. Salting out refers to the addition of a salt solution before No. 40 to the protein solution, so that the solubility of the protein decreases and precipitates.

5, Yes, the last of our senior year of high school is the complete interpretation of the college entrance examination, which is very good, and almost all inductions are available.

1.No, the former has to be crystallized. Cooling crystallization is the use of different solubility at different temperatures, and evaporation crystallization is the evaporation solvent.

Separation of solid and liquid states. Recrystallization is to dissolve first and then crystallize, solid to liquid and then solid.

2.Generally, the solid reacts with dilute nitric acid, such as Cus, which is only soluble in dilute nitric acid, insoluble in HCL and water.

3.They are light green, yellow, and blue (of course, it has a little relationship with anions, but don't worry about it) 4Dialysis is generally done with semi-permeable membranes, and salting out is used to alter solubility (like extracting proteins)5. 6。。

The interest is similar, you can exchange it. If something is wrong, please refer to it.

1.Evaporative crystallization is a type of crystallization process; Evaporation refers to the process by which a liquid becomes a gas – it should not be a concept.

Evaporation crystallization refers to the process in which the solvent is evaporated and the solute is crystallized and precipitated after the supersaturated state; On the other hand, cooling crystallization refers to the process of crystallization and precipitation of solute supersaturation after the solvent is cured; Both are separated from the liquid and the solid;

Recrystallization refers to the process of dissolving and recrystallizing the crystalline substance again after a crystallization process, and in general, the purity of the recrystallized substance will be greatly improved.

2.Dilute nitric acid has an oxidizing effect, which is different from the oxidation of concentrated nitric acid - similarly, it is different from water, dilute hydrochloric acid, etc.

3.divalent iron ions, green; ferric ions, yellow; Divalent copper ions, blue - the color here is based on the common chemical products and concentrations, because the concentration and anions may be different, so the color of the ions can not be used as a basis for identification.

4.Dialysis is a means of separation in which the hypotonic side transfers liquid to the hypertonic side, while the hypertonic side transfers solutes to the hypotonic side.

Salting out is a different concept, through the change of factors such as the weight ion strength of the solution, a certain solute is passively supersaturated, so as to obtain crystallization separation;

5.Separation and purification are very important applications of chemistry, learn hard, and you can use them in the future. A little personal opinion should magnify the difference between the component to be separated and other components as much as possible, and repeat it many times if necessary.

For example, solubility, melting point, electrochemical properties, physical properties, etc. For example, chromatography, a method of separation and purification that you will learn about in the future, is to adsorb-desorption multiple times according to the difference in the dissociation rate of the components in the mobile phase and the stationary phase, so as to achieve the separation. A simple example of recrystallization, like the one mentioned above, is actually based on the difference in solubility between the target component and other components, which is amplified twice or more to "separate" and "purify" the target component.

6.It's hard to say.

I've always been very fond of chemistry and want to communicate more.