May I ask you who knows the simple chemistry problem r urgency, I thank you in advance 0K

1. d

2.b Sound waves transmit energy, and strong sound waves can even break glass (you must have seen it in the movie).

c Prove that sound can travel through the air at the speed of sound.

d Sound travels at different speeds in different media, such as air, water, and iron. are all different.

Hydrated lime Ca(OH)2 is easy to react with carbon dioxide in the air to deteriorate hydrated lime, Ca(OH)2+CO2=CaCO3+H2O

Burying hydrated lime in the ground can isolate carbon dioxide, making hydrated lime less susceptible to deterioration.

Try to avoid the reaction caused by contact with air: Ca(OH)2 + CO2 = CaCO3 + H2O

The advantage is to avoid exposure to carbon dioxide in the air and deterioration [ Ca(OH)2+CO2=CaCO3+H2O].

2nabr+cl2--2nacl+br2

Let the NABR participating in the reaction be X, then the resulting NaCl is 117x 206, and the NABR that does not participate in the reaction is 206-X

Because evaporation gives 126 grams of solids. The NABR that did not participate in the reaction and the resulting NACL yielded 117x 206 + (206-x) = 126x =

x=checked. It should be this.

You can ask the teacher, you can't ask the teacher, you can't ask the teacher, you can't ask the classmates, you don't have time to check the information, and I can't give you specific data.

What you get is bromine then.

Molar mass of bromine Molar mass of chlorine.

--=---126 Mass of chlorine The quality of chlorine.

--The volume of chlorine gas.

Molar mass of chlorine.

The quality of chlorine. --1 2* molar mass of sodium bromide = molar mass of sodium bromide used, molar mass of chlorine.

NABR: NACL = 206:117 - NACL = NABR (participant) * 117 206

From the question, NACL+NABR(not participating)=126g, so 206-NABR(participating)+NACL=126g

Get NABR (participated) = 80 89g

n) nabr (participate) =

n)cl2:(n)nabr=1:2

So cl2=

cl2(v)=

It can be known according to the chemical formula.

nacl mgcl2

Because the ratio of the amount of sodium ions to magnesium ions is 3:2

So the mass ratio of the two substances is.

nacl:mgcl2=3:2

Let NaCl be x mol and MgCl2 be y mol, so there is x+2y=28

x:y=3:2

So we get x=12 y=8

So the mass of NaCl is MgCl2=95*8=760g

The mass ratio is 411:380

Sodium chloride is 822g

Magnesium chloride is 1520g

: From the ratio of ions: the mass ratio of the two substances: 3:2 From this, the mass ratio can be obtained.

The ratio of the amount of sodium ions to chloride ions in sodium chloride is 1:1, whereas the ratio of the amount of magnesium ions and chloride ions in magnesium chloride:

1:2, and because chloride ions are 28mol in total, let x 3x+4x=28, so x=4, so sodium chloride is 3*4 mol, and magnesium chloride is 2*4mol, and then multiply the respective formulas to find the solution.

Choose b and d

Explanation: Ethanol contains ethanol molecules, and each ethanol molecule contains 5 c-h, so it contains; A false;

15g formaldehyde is, the number of oxygen-containing atoms is, 15g acetic acid is, and the number of oxygen-containing atoms is, so b is correct;

1molCl2 and 1molH2O fully reacted, and the number of H+ ions generated was 2Na, so C was wrong;

Under standard conditions, heptane is, formed after complete combustion, so d is correct.

Support Zhang Ming's.

The reason is as he said, "If it can be collected by draining water (it can't be carbon dioxide), and the bottle mouth is placed upwards (it can't be hydrogen), it should be oxygen."

Procedure: Insert a wooden stick with sparks into the bottle.

Phenomenon: Re-ignition of wooden strips.

Conclusion: This bottle of gas is oxygen.

(1) Support Zhang Ming's view.

2) Put a burning stick of wood near the mouth of the bottle, and the result: the stick burns more vigorously, indicating that the gas is oxygen.

In the case of hydrogen, the gas inside the bottle is burned.

In the case of carbon dioxide, the sticks are extinguished immediately.