A chemistry fill in the blank question

1) Process Indicates that the colorless solution is acidic.

2) Process Description: The colorless solution reacts with magnesium to produce hydrogen.

3) Process Indicates that the colorless solution has sulfate.

This colorless solution may be an HSO4 compound such as NaHSO4 or KhSO4.

or sulfuric acid H2SO4 + mg =H2 +mgSO4 or 2NaHSO4 + mg =H2 +mgSO4 + Na2SO4

2h2 + o2 = 2h2o

bacl2 + h2so4 = baso4↓ +2hcl

1)h2so4

2) H2SO4 + MG = MGSO4 + H2 (gas arrow) BACl2 + H2SO4 = BASO4 (precipitation) + 2HCl2H2 + O2 = (ignition) 2H2O

According to the knowledge (1) and (2) that the solution is an acidic solution, and the eradication of (3) shows that the solution contains sulfate, so the answer is:

1) Sulfuric acid solution.

2）h2so4 + mg ***** h2↑ +mgso42h2 + o2 ***** 2h2o

bacl2 + h2so4 *****baso4↓ +2hcl

The purple litmus solution turns red – the solution is acidic.

The gas was collected and found to be combustible and the only product of combustion was water – the gas was hydrogen.

It was found that there was a white precipitate insoluble in dilute nitric acid - the precipitate was barium sulfate.

1) The solution is H2SO4 solution (sulfuric acid) 2) Write out the equation for the chemical reaction described during the verification process.

mg+h2so4*****mgso4+h2↑ 2 h2+o2*****2 h2o bacl2+h2so4===baso4↓+ 2 hcl

1) It is acidic (2) It generates hydrogen and can dissociate hydrogen ions (3) It generates barium sulfate precipitate with sulfate.

1) The solution is a sulfuric acid solution (I think it may be, like sodium bisulfate, I don't know if it's right).

2) Write out the equations for the chemical reactions described during the verification process.

Magnesium and sulfuric acid produce magnesium sulfate and 2 hydrogen.

2 Hydrogen + Oxygen = 2 Water.

Sulfuric acid + barium chloride = 2 hydrochloric acid + barium sulfate precipitation.

Sorry, I don't know which equation to play.

H2SO4H2SO4+MG=MGso4+H2 gas symbol.

1H2+O2 = ignite 2H2O

BACl2+H2SO4=2HCl+BaSO4 precipitation symbol.

A positive 2-valent metal gram fully reacts with gram of dilute sulfuric acid (a sufficient amount of brother-qin), the metal is all dissolved, and the mass of the remaining substance is gram, then the chemical equation of the reaction between the metal and dilute sulfuric acid is (mg+h2so4=mgso4+h2, generating hydrogen (

g, he(mol. The molar mass of the metal m is (24

Gramo. According to the conservation of mass, the reduced mass is the mass of hydrogen, the positive 2-valent metal m 1molm

Exactly 1mol is produced

Hydrogen, therefore,

Cl- is only present with KCl, MgCl2, C(K+)=, C(Mg2+)=Cl- can only be provided, and also in Mg(NO3)2.

c(no3-)=

From the yin and yang example charge conservation gets:

c(k+)+c(mg2+)*2=c(cl-)+c(no3-)

So the answer is.

Yes!! You can do it with the conservation of charge!! The solution is neutral and the total charge of all ions is 0

(1) Connecting instruments and devices and checking the air tightness of the devices.

Device air tightness check: first put one end of the catheter (immersed in water), close it with your hand (the outer wall of the instrument), stop for a while, if the catheter mouth (bubbles), release the palm, the catheter mouth has (water column rises), stop for a while, the water column does not fall, it means that the device does not leak.

2) Filtration Operation precautions: one sticker, two low, three stickers: the inner wall of the filter paper (close to the funnel) shall not leave bubbles.

Two low: 1 The edge of the filter paper is lower than (the inner wall of the funnel) 2 The liquid level in the funnel is lower than (the edge of the filter paper).

Three backs: 1 The nozzle at the lower end of the funnel is close to the beaker (inner wall).

2 When draining with a glass rod, the lower end of the glass rod is lightly against one side of the filter paper (three layers)3 When draining with a glass rod, the tip of the beaker is close to the middle of the glass rod.

Possible reasons why the filtrate remains cloudy after filtration are:

1 (the instrument is not clean), 2 (the filter paper is broken), 3 (the liquid level in the funnel is higher than the edge of the filter paper).

1. Immerse yourself in water.

The bottom of the tube. There are bubbles popping up.

A section of water column. Second, cling.

Upper edge of funnel mouth filter paper.

The inner wall is three-layered. 3. The beaker that receives the filtrate is not clean.

Pour the liquid above the edge of the filter paper.

Molecular formula CH3CH2OH---CH2=CH2+H2O (concentrated sulfuric acid, 170).

The effect of the NaOH solution is (3.)

In which reaction or in which aspects?

The first null is the molecular formula, and the equation for laboratory-made ethylene is: CH3CH2OH - >CH2=CH2+H2O (needs to be under the condition of concentrated sulfuric acid and 170 degrees).

1> The greater the solubility, the more solids will be washed out after evaporating the water. In the figure, at t2, the solubility of A>B>C, so the answer to the first question is A;

2> At t1, the solubility of the three substances is B>A=C. Therefore, when the t1 condition is used, the order of the mass fractions of the three is B>A=C;

However, after the temperature change, the three substances A and B are still saturated solutions, and C is an unsaturated solution. So the mass fraction of C is less than that of A.

Summary: The relationship between mass fraction is B&A&C.

1, A2. B, A, C.

There is no solid existence, so even if the cooling of C is still so much, it will not increase, so C is smaller than A.

(1) At t2, the three saturated solutions are evaporated with the same mass of water at a constant temperature, and the most crystals are precipitated according to the amount of dissolved solute when the same water is saturated.

2) When the three saturated solutions are cooled from T2 to T1 respectively, the mass fraction of solutes in the obtained solution is in the order of large to small: B, A, C, A, B, Saturated, and C is unsaturated.

It can be seen from the chemical formula that the original nitrogen element valency in NH3 is -3, after participating in the chemical reaction, the valency of nitrogen element in NH4Cl is -3, and the valency of nitrogen element in N2 is 0, that is, the oxidized N atom is 2, and the nitrogen atom that has not been oxidized is 6, and the ammonia molecule (NH3) contains N is 1, that is, the mass ratio of ammonia is equal to the mass ratio of N, that is, 2:6=1:3

a：h b：o c：na d：cl

2Na+O2=(heated) Na2O2 If it is at room temperature, then 4Na+O2=2Na2O, but not yellow.

H2+Cl2 = (light or ignition) 2HCl

A: Hydrogen B: Oxygen C: Sodium D: Chlorine.

2) C+B: 2Na+O2=(ignition)=Na2O2

A+D: H2+Cl2=(Ignition or Light) = 2HCl

The flame color of c when it is burned is yellow when it reacts, and c is NA

So a is h (there is only one electron in the outer shell, and the reaction is light. The elemental element of C reacts sufficiently with the elemental element of B at high temperature to produce a yellowish solid compound (atomic number relation ab c).

It can be seen that B is OA and D can have a chemical reaction, and the reaction conditions can be ignition or light, and D can be known to be Cl (short-period element).

1）a：h b：o c：

Na D:Cl(2) Write the chemical equation 2Na+O2=Na2O2 (Condition: High Temperature) H2+Cl2=2HCl (Condition:

Ignite or light).

Analysis: It is known that there is only one electron in the outermost shell of a and c atoms, and the flame color of c when it is burned is yellow when it reacts, so it is inferred that c is na (sodium element).

The element of C can fully react with the element of B at high temperature to produce a light yellow solid compound, so it is inferred that the light yellow compound is Na2O2 (sodium peroxide), so it is inferred that B is O (oxygen element).

A and D can undergo a chemical reaction, and the reaction conditions can be ignition or light inference, A and D may be gases, and the outermost gaseous element with only one electron is only H (hydrogen), then D is Cl (chlorine).

1）a：h； b：o； c：na；D: Cl(2)2Na + O2 (Na2O2H2 + Cl2 (ignition or light) 2HCl

4gnaoh is, assuming that the sodium ion is 1mol, then the water has 100molAnd if there are sodium ions, the water is 10molThere are hydroxides. Hydrogen ions are required, and a sulfuric acid molecule has two hydrogen ions, so the mass of sulfuric acid is required to be grams.

At the same time, chlorine gas is generated.

Chloroform is composed of a total of 3 kinds of C H Cl.

Chloroform is an organic compound. It is burned in the air to produce carbon dioxide, water and chlorine. It has been determined that chloroform can be completely reversed with oxygen to produce grams of carbon dioxide and bidlingke water, and at the same time to produce chlorine gas.

From the above data, it is inferred that chloroform is composed of three elements: C, H and Cl.