3 high school chemistry questions, who will help?

Wait, I'm sorry, I didn't see the third question clearly. 3.A certain plant nutrient solution is known to be formulated with KCl, K2SO4, ZNSO4 and 1LH2O so:

n(kcl) = mol; n(k2so4) = mol;n(znCl2) = mol and m(kCl) = 31+ = (g mol); m(k2so4) = 2×39+96 = 174 (g/mol); m(zncl2) = 65+ = 136 (g/mol).So m(kcl) = = g m(k2so4) = = g m(zncl2) = = g

Please ask the question, this question should be selected c with 1 5g aluminum and magnesium.

Here's why. of H2SO4 reacts with aluminum and magnesium, respectively.

Aluminum is magnesium. According to the reaction equation.

Mg + H2SO4 = MgSO4 + H2AL + 3H2SO4 = 3H2 + AL(SO4)3 It can be seen that both aluminum and magnesium are in excess.

Then the reaction falls into the solution, and the non-reaction is in the beaker.

So the mass on both sides is added.

Then according to the concentration of the acid, it can be seen that hydrogen gas is produced.

So the mass on both sides decreases.

So weight gain on both sides.

Select C upstairs, concentrated sulfuric acid is 98%, 1mol l is not considered concentrated sulfuric acid, sodium will react with water, and there is Lishijunzong said, the quality of the addition is not the same, remove the same amount of hydrogen, or different.

First of all, 1mol l is concentrated sulfuric acid!

Metals such as iron, aluminum, zinc, etc., are passivated in cold concentrated nitric acid or concentrated sulfuric acid.

These metals are not very reactive, but they are not incapable of reacting with dilute acids.

It is also said that the balance is balanced, so the mass is equal.

It should be b with 1 5g aluminum and zinc.

By the way, do you think that going out as much and adding different things can be balanced???

This should be a multiple-choice question.

Let's start with the case of purity.

CaCO3 + 2HCl = H2O + CaCl2 + CO2100g calcium carbonate produces carbon dioxide.

10 g calcium carbonate carbon dioxide.

NCO2=So CAC3=

So when it's pure, exactly 10g of calcium carbonate produces CO2, but the title says it's impurities.

So we can think of it this way.

The average amount of CO2 produced by impurity A and impurity B is the same as that of calcium carbonate, and the amount of carbon dioxide produced by magnesium carbonate is 84g, and silica is not produced (greater than calcium carbonate).

So they can produce the same average value as calcium carbonate.

It is estimated that several other options are either greater than calcium carbonate or all are smaller than calcium carbonate.

In general, wild acres or Fe react with S and Fes will form Fes, so the purpose of this question is to ask whether solid M is Fes and whether there will be unreacted Fe or S

Dilute sulfuric acid reacts well with solid M to form H2S, and if M still has Fe, H2 is also formed

After the reaction stopped, device B increased its weight, and B was NaOH, that is, H2S was absorbed

There is no change in the solution in the C device, C is CuSO4, which means that there is no H2S here, that is, there is enough NaOH to absorb all H2S

The volume of gas entering the trachea after the reaction is vml (converted to standard condition), indicating that there is a gas insoluble in water that is collected, that is, there is H2

From the above experiments, it can be seen that:

1) The substances that must be contained in solid M are (fill in the chemical formula): Fes and Fe

The reason is: NaOH weight gain, indicating the generation of H2S, that is, there is Fes in the solid M, and finally there is gas left, that is, the generation of H2, that is, there is Fe in M

The mass of the total substance after which is g

I don't understand this sentence.

According to the volume of H2 vml, the mass of Fe is 56V 22400

G is based on the mass of NaOH gain, i.e. the mass of H2S, and the mass of Fes.

2) Write the ionic equation for the reaction of the B device.

2oh-h2s

S2-2H2O, note that there is an excess of NaOH, i.e., S2- is generated

3) What is the role of the C device to prove whether the H2S is completely absorbed by NaOH or not.

If there is no device B in the experiment, then what is the phenomenon of digging resistance produced in device C produces a black precipitate, i.e., the reaction H2S occurs

cuso4cus

H2SO44) dilute sulfuric acid and solid M after the reaction of the solution still residual light yellow solid, the solid is may be S, note that there are only 3 light yellow solids in the middle school stage, S element, AGBR precipitation, Na2O2, here can only be S

To isolate the solid, what is the glass instrument used in the experimental operation in addition to the beaker: note that it is a glass instrument, and it is a filtration operation, so it is a loophole and a glass rod.

We analyze this process: why does the precipitation start when the AMLNAOH solution is added, because the NAOH reacts with HCl first, and when the HCl is consumed, the NAOH starts to react with ALCL3, and A has been consumed at this time

The reaction equation for the precipitation of MLOH is: AlCl3+3NaOH=Al(OH)3

H2O (exclamation mark indicates precipitation symbol, computer technology is not up to par, will see) when the amount of precipitation is maximum?

Obviously, when NaOH reacts completely with AlCl3, that is, when the ratio of the amount of NaOH to AlCl3 is 3:1.

3mol of sodium hydroxide produces 1mol of precipitation, why is the amount of precipitation equal in the addition of BML and CML?

Because NaOH + NaOH = Naalo2 + 2H2O, that is to say, 1molNaOH dissolves 1molNaOH

Then we can draw a diagram of the relationship between the amount of precipitation and the amount of NAOH added based on this information: as follows: why don't the slopes of the two straight lines wait for my analysis above?

According to this diagram combined with the knowledge of trigonometric functions, it is easy to find the abscissa of the highest point, and the answer does not need to be said!

I have to follow my guidance to the end result.

It makes more sense!

1b (neutralized first, in the production of magnesium hydroxide and aluminum hydroxide, aluminum hydroxide is dissolved in a strong alkali) 2naOH (sodium sulfate has no phenomenon, magnesium chloride is white precipitate, ferrous chloride is white first white and then gray-green and then red, aluminum sulfate is white precipitated and then dissolved, ferric chloride is red precipitate) 3 will not be temporarily 4 Add a strong acidic solution to adjust the pH to 4-6

1) Only the valency of MN is reduced, from the +7 valence in potassium permanganate to the +2 valence in manganese sulfate, which is reduced by 5, and the stoichiometric number of the former Tong Zheng wide side is 2, 5 times 2 is equal to 10, so the total number of electrons transferred is 10, 10mol electron transfer, corresponding to 2mol potassium permanganese leucate is reduced, so when 1mol electrons are transferred, potassium permanganate is reduced. In this reaction, a total of 5mol 32g mol=160g s is generated, that is, 5mol s are reduced, so when 80g s are analyzed, H2S is oxidized.

The rise and fall of the standardized valence will be known.

1) 10 permanganic acid lease repentance friend wheel potassium 85 oxidation.

2) 3

3)cu2+ o2- o2 cu2o

Solution:1The molar mass of the gas under standard conditions is.

m=m n n= solution m=

2.This is better with the cross method, but it is not a general cross, the molecular weight of O2 is 32, the molecular weight of N2 is 28, m=(32*2+28*8) 10=

3.The molar mass of the gas under standard conditions is , that is, so the mass m1 of co2 is and the rest is the mass m2=m-m1=

The volume of co2 is, the volume of co2 v2 = n2 * *

I think back then, the first prize in the chemistry competition, I didn't study chemistry for many years.

m=m/n=

3.Let the amount of CO be x and CO2 be y

28x+44y=

x+y= solution x= y=

So the volume ratio is 1 to 4

The mass ratio is (add the unit yourself.

1:2: (32x2+28x8) Note: The mixing volume is set to unchanged)3:;