Come on. Chemistry questions, chemistry problems, the masters come

Solution: (1) The relative molecular weight of the hydrocarbon: h: 72*1 6=12 12 1=12.

C: 72*5 6=60 60 12=5 (2) The molecular formula of the hydrocarbon: C5H12 There are three types of pentane: n-, isopentane, and neopentane.

Four chlorinated substances: 2-methylbutane CH3-CH2 CH3CH34) hydrocarbon A can be prepared by addition reaction of another hydrocarbon B. The hydrocarbon BCH2==C-CH2 CH3 and, of course, 2-methyl-2-butene.

CH33-methyl-1-butene. 3-Methyl-1-butyne.

Untie. BL hydrocarbons are available. And let the hydrocarbon be CXHY. According to the title. It can be seen that there is 12x y=5 1

Y = 12 5x is obtained, so the hydrocarbon is CXH12 5x. After learning this.

Because there are BL hydrocarbons. So the amount of matter is b. The quality is.

So you can list equations.

b solution x=5. So the hydrocarbon is C5H12 for pentane. The relative molecular mass is 72 in the third question. Structural shorts should be written taking into account all isomers.

So there are 1, ch2cl-ch2-ch2-ch2-ch32, ch3-chcl-ch2-ch2-ch33, ch3-ccl-ch2-ch3

ch34、 ch2cl

ch3-c-ch3

CH34) alkanes can be obtained by addition of olefins.

So you can use c5h10+h2 c5h12

One of the pentene structural formulas is CH3-CH2-CH=CH-CH3

1) The relative molecular mass is: 12*5+1*12=722)(5:1) (12:1)=5:12; (Ratio of the number of atoms) The molecular formula is: C5H12

3) Hydrocarbon A:2-methylbutane structure simplified formula: CH3CH2CH(CH3)24) Hydrocarbon B:2-methyl2-butene structure simplified formula: CH3CHCh3)2

SO2 is a gas, oxygen is another gas, of course it does not contain oxygen B, water in nature will dissolve a small amount of oxygen in the air (oxygen can be dissolved in water) C should be needless to say, the air contains oxygen.

Liquid oxygen in d is liquid oxygen, which of course gets oxygen after evaporation, just like water evaporates to get water vapor.

The answer is a

Oxygen is dissolved in water in nature.

There is oxygen in the air to breathe.

Oxygen gas is formed after the evaporation of liquid oxygen.

It should be A, there is dissolved oxygen in the water, there is oxygen in the air, and the liquid oxygen is oxygen after evaporation!

It's a bWater in nature is not pure, it is dissolved in oxygenWherever there is air, there will be oxygen.

d.The gas obtained by the evaporation of liquid oxygen is, of course, oxygen, (oxygen has a lower boiling point than nitrogen) aSulfur dioxide is SO2 is this substance, compound.

SO2 is pure, what does the fish in the water suck, liquefied oxygen vapor is still oxygen, and the air is a mixture that cannot be pure.

Not included! Matter is made up of molecules or atoms, and molecules are made up of atoms or ions.

2h2+o2=2h2o

1g-8g--9g---

If 9 grams of water are generated, the hydrogen and silver participating in the reaction will be 1 gram of gas, and the oxygen will be 8 grams.

If the mass ratio of hydrogen to oxygen in the container is 3:2, the oxygen contains 8 grams, and the hydrogen remains.

Set up containers. Medium hydrogen is x grams.

3:2=x:8, x=12 grams.

12 + 8 = 20 (grams).

A: The total mass of the original gas mixture is 20 grams.

Organic matter and grams of oxygen produce grams of water and grams of carbon dioxide.

The gram of water contains the element of hydrogen grams, and the element of oxygen grams.

grams of carbon dioxide contain grams of carbon and oxygen.

Grams of organic matter contain grams of carbon, hydrogen and oxygen.

Therefore, the organic matter is CH4O.

3.Let it generate x kilograms of oxygen.

2h2o=2h2+o2

36:32=:x,x=kilogram=4800 grams, thousand grams = 600 grams.

4800 liters.

600 liters.

A: 3,359 liters of oxygen and 6,674 liters of hydrogen were generated.

4.Set 68 g H2O2 to produce x g of oxygen.

2h2o2=2h2o+o2

-68g---x

68:32=68:x, x = 32 grams.

Let y grams of aluminum react exactly exactly with 32 grams of oxygen.

4al+3o2=2al2o3

y---32

108:96=y:32, y=36 grams.

2g-16g--18g

To produce 18 grams of water, 2 grams of hydrogen and 16 grams of oxygen are required, and the mass of nitrogen is 2 grams.

Oxygen Mass Generated:

2kmNO4 = K2mNO4 + MNO2 + O2 grams.

Answer: The remaining solid contains KMNO4

g, k2mno4

grams, mno2 grams.

4oh- +4e-=o2+2h2o

The increase in pH is essentially equal to the electrolysis of water with anode hydroxide and cathode hydrogen ion discharge. Therefore, the concentration of sodium hydroxide increases.

I won't repeat it here.

2naoh+cuso4=cu(oh)2↓+na2so480---98 --14240*10%--y---xx=7,y=

The mass fraction of the solute in the resulting solution = 7 (40+.)

2naoh+cuso4=cu(oh)2↓+na2so480 98 142

4. The mass fraction of the solute in the resulting solution.

Let the oxide chemical formula of 1mol of this nitrogen be nxoy

Then the mass ratio of the n,o element is:

14x:16y=7:8

x:y=1:1

o is -2 valence.

n is +2 valence.

with proportions. Mass o:n=8:7, that is, the expansion ratio of 16:14 can be spelled as no (the question says that this is an oxide), so n is +2 valence.

nn:no=7/14:8/16=1:1

So the simplest form is: no

So the chemical formula is: (no)n

The n valency is +2 valence. ok？

Analysis: The chemical formula of the nitrogen oxide is nxoy, which has been obtained from 14x 16y = 7 8;, x y=1:1, so the chemical formula of the oxide is no; The valency of n is +2 valence.

So the valency of the chemical formula nu,n is +2