High One Chemistry! Hurry! There are points plus!!

ABA C2H4 is selected, 3 molo2 is required for complete combustion, 3 molo2 is required for complete combustion to produce 2molCO2, and 2molCO2 is required for complete combustion to produce 2molCO2

D ch3COOH needs 2 molo2 to burn completely, and 2mol CO2 can be used to separate different atoms, amol carbon atom consumes amolo2, bmol hydrogen atom consumes b 4molo2, there are c oxygen atoms in the molecule, subtract c 2 molo2If there are amols of carbon, amolCO2 is formed, and bmol of hydrogen atoms is b2mol of water.

To sum up, the molecular formula Cxhyoz, the amount of O2 required for complete combustion: (X+Y 4-Z2)mol; CO2 xmol is generated; H2O y 2mol is generated.

Write out four combustion chemistry equations at a glance. b

1mol of steam of a certain organic matter, completely burned to produce 2mol of CO2, that is to say, there are two C's in the organic matter, excluding Cd, the answer can already be obtained, because it is the steam of a certain organic matter, so only B is liquid, it will have steam, A is a gaseous substance, so the answer is B

Analysis: (1) When the lever is an insulator, only the Fe pole reacts with the solution CuSO4, Fe+CuSo4=FeSo4+Cu, 1molFe generates 1molCu, and the mass of 1molCu is greater than the mass of 1molFe, so at this time, the B end sinks, that is, the B end is low.

2) When the lever is a conductor, Fe and Cu and CuSO4 constitute the galvanic cell, Fe is the negative electrode, Cu is the positive electrode, CuSO4 is the electrolyte solution, the battery reaction is Fe + CuSO4 = FeSo4 + Cu, and the Fe electrode loses electrons due to being the negative electrode, and the mass decreases. The Cu electrode is positive, where the Cu2+ ions in the solution become Cu and attach to the surface of the Cu electrode, thus increasing the mass.

Therefore, at this time, the A end sinks.

To sum up, choose D.

Select D, when it is an insulator, only Fe reacts with the solution CuSo4, Fe+CuSo4=FeSo4+Cu, iron replaces copper, and the mass of the replaced copper is greater than that of iron, so the B end is lower.

When it is a conductor, Fe and Cu and CuSO4 constitute a galvanic cell, Fe is the negative electrode, Cu is the positive electrode, and CuSO4 is the electrolyte solution, and the reaction that occurs at this time is also Fe + CuSO4 = Feso4 + Cu, but at this time Fe is the negative electrode and loses electrons, and the electrons flow along the conductor to the positive electrode, and the Cu2+ ions in the solution are at the positive electrode, that is, the Cu pole gets electrons, becomes Cu, and attaches to the surface of the positive electrode, so that the A terminal is low.

1.(NH4)2SO4 + CA(OH)2 = (heating) 2H2O + CASO4 + 2NH3 NH3 +H20 =

BaCl2+(NH4)2SO4=BASO4(precipitation)+2NH4ClagNO3+NH4Cl=AGCL(precipitation)+NH4NO32 agcl

Four packets of powder are dissolved in water, and four test tubes are taken, and a small amount of four solutions are added respectively.

1.Add BACL2 dropwise, there is precipitation production, filtration, precipitation dropwise nitric acid, there is gas released is (NH4)2CO3, insoluble is (NH4)2SO4

2.Add Na2SO4 dropwise, and there is a precipitate insoluble in nitric acid is BACL23Add AgNO3 dropwise, there is a precipitate, insoluble in nitric acid is KCL, and there is no reaction in Ca(NO3)2

1) Experiment 1: NH4+ +OH- = NH3 +H20 NH3 +H20 = alkaline).

Experiment 2: Ba2+ +SO42- = BaSO4 Experiment 3: AG+ +Cl- =AGCL

2) The chloride ions in the solution react with the silver ions in the silver nitrate to produce precipitation.

3) KCL: Cl- was tested with silver nitrate, and potassium ions were reacted with flame color; (NH4)2SO4: strong alkali and slight heat for ammonium ions, soluble barium salt for sulfate; (nh4)2co3：

Ammonium ions with strong alkali and slightly heated, carbonate with soluble calcium salt, hydrochloric acid and clarified lime water;

It should be two constant temperature containers, A and B, right?

The so-called conversion rate is only related to the result, not the process! Therefore, it is enough to compare the amount of matter A with the amount of matter at equilibrium with the amount of substance at B. It has nothing to do with how the reaction moves after a reactant is added, and the final conversion rate of the reaction is the same regardless of whether a mol A is added or A mol B is added.

In this problem, the reaction after adding a must be apparently shifted to the right, but after equilibrium, there is:

Container A: Because the pressure is unchanged, the reaction progress is the same, the ratio of the amount of substances A and B is unchanged, and the conversion rate is unchanged; (Because the container can become larger, it can also be understood as putting the added A into another container with the same pressure to react by itself).

Container B: Add gas, the volume remains the same, the total pressure becomes larger, and the reaction generally moves in the direction of volume reduction, so the conversion rate decreases.

PS: Don't think about static issues with a dynamic mindset.

Select C 1 is the concentration, the pressure is unchanged and increases, and 2 is the increase in pressure.

(nh4)2co3 == 2nh3 + h2o + co2

The resulting 2NH3 + H2O + CO2 are all gases.

So the average relative molecular mass of the decomposed gas mixture = (2*17 + 18 + 44) 4 = 24

It can be seen that after the composition is decomposed, it is generated: 2NH3 1CO2 1H2O200 degrees Water is gaseous.

Then the average relative molecular mass is (2*17+1*44+1*18) 4=24, I hope it will help you.

1) Remove the small sodium block from the large sodium block, the nature of the metal sodium is small softness and hardness, and the small sodium block should be sucked (wiped) with filter paper, and the purpose of this is to wipe off the surface kerosene to prevent interference with the subsequent test.

2) Occurrence**; Floating on the surface The main reason for this phenomenon is that sodium is less dense than water, and the release of H2 increases buoyancy.

3）2na+2h2o==2naoh+h2 ;phenolphthalein with an acid-base indicator; The method of hydrogen testing is to collect a small test tube of hydrogen with the drainage method, block the mouth of the test tube with your thumb, release your thumb close to the flame to ignite the gas, and hear a slight popping sound.

(1) The hardness of Na is small in order to absorb the kerosene on the surface of Na.

2) The undesirable consequence is that ** A is manifested by a violent reaction and a "hissing" sound and no rotation of the picture.

3) 2Na+2H2O=2NaOH+H2 The indicator is phenolphthalein Collect the gas produced by its reaction with a small test tube, remove it and ignite it, emit a light blue flame and there are water droplets on the inner wall of the test tube, and there is no turbidity after pouring clear lime water**, which means that the gas is hydrogen.

1 na is relatively soft and absorbs kerosene on the surface.

2 No diagrams.

3 2Na+2H2O===2NaOH+H2 phenolphthalein ignited, cover a small beaker with dry and cold above the flame, the pure gas can burn quietly, there is a light blue flame, and there are small water droplets on the inner wall of the beaker.

(1) The hardness of sodium is low and can be cut. In order to absorb the kerosene (2) reacts violently, the heat can not be dissipated in time, and it may not be seen in the figure behind ** (3) 2Na + 2H2O = 2NaOH + H2, phenolphthalein, ignite the gas with a dry beaker and cover it above the flame, and there are small water droplets on the wall of the beaker, which proves that it is hydrogen.

1 Na soft absorbs kerosene from the surface.

2 **。3. Cover a small beaker with dry and cold above the flame, the pure gas can burn quietly, there is a light blue flame, and there are small water droplets on the inner wall of the beaker. 2na+2h2o=2naoh+h2

Soft, remove the oil on the surface of sodium, ** (hydrogen escapes out, sodium reacts with water and releases a lot of heat), hey it's too simple to be lazy.

(1) Na soft In order to absorb the kerosene on the surface of NA (2) ** occurs and causes an accident.

A. It reacts violently and makes a "hiss" sound and floats on the surface of the water and swims around.

3) 2Na+2H2O=2NaOH+H2 The indicator is colorless phenolphthalein (liquid will turn purple).

Use a small test tube to collect the gas produced by its reaction, remove it and ignite it, emit a light blue flame and there are water droplets on the inner wall of the test tube, and there is no turbidity after pouring clarified lime water**, indicating that the gas is hydrogen.

I'm a freshman in high school. Chemistry Compulsory 1 Chemical Properties of Metals is available in that chapter.

1, (1) Because it is a reversible reaction, N2 and H2 will not all be converted to NH3, so the heat released should be less.

2) The reaction is exothermic and can be cooled.

2. The container is closed and the volume remains unchanged, remove PCL3 and CL2, the reaction will move to the left, select C

I didn't learn anything about equilibrium constants in high school, and I didn't know much about the third.

1. (1) Part of the heat is absorbed by the catalyst.

2) Adopt pressurized and cooling conditions.

2、d3、

One: 1 Because the positive reaction of the reaction is an exothermic reaction, the heat will be absorbed by the reverse reaction, so the measured heat is always less.

2 Increase the pressure or decrease the temperature.

MgCl2·6H2O is dissolved with water, and Mg(OH)2 precipitate may be generated during pre-ammoniation, and then NH3 and NH4HCO3 are added to obtain MgCO3, and basic magnesium carbonate is further obtained by thermal hydrolysis.

1. The above filtrate is concentrated and crystallized, and the obtained solid is used as ammonium nitrogen fertilizer, raw materials for zinc-manganese dry batteries, and so on.

2、mg2+ +2nh3 + 2h2o = mg(oh)2↓ +2nh4+。

3. If the temperature is too high, the basic magnesium carbonate generated may be decomposed by heat.