Simple chemistry questions in high school, easiest problems in chemistry high school

The chemical state is the state of the compound, and the free state is the elemental state. For example, Cl in NaCl is a chemical state, and Cl in Cl2 has a free state.

There are two forms of elements in nature, free state and chemical state, free state actually refers to the elemental form, and the chemical state is of course a compound, for example, the chlorine element in Cl2 is the free state, and the chlorine element in NaCl is the chemical state.

The disproportionation reaction refers to the change of valency of the same element from the middle to both sides in the redox reaction, such as Cl2 + NaOH = NaCl

The valency of chlorine in the Naclo + H2O reaction changes from 0 valence to +1 and -1 valence, respectively, and the reaction is a disproportionation reaction.

In addition, the normalization reaction and the disproportionation reaction are just the opposite, which is caused by the same element in the redox reaction, the valency of both sides to the middle, such as SO2 + 2H2S = 3S + 2H2O, of course, whether it is disproportionation or neutralization, the valency does not have to be the same.

Autooxidation reaction means that in the redox reaction, the valency of elements in a substance increases and decreases, such as 3NO2 + H2O = 2HNO3 + NO, which is the redox reaction of NO2 itself.

No, the chemical state means that the element exists in the state of a compound, and the free state means that the element exists in an elemental form. Disproportionation reaction is a reaction in which the valency of an element rises and falls, and its own redox is reduced.

Because the ions that form the electron shell structure of the noble gas element after they get electrons are only reducible, not oxidizing, that is, they have lost the ability to get electrons again!! (Hopefully I've made it clear.) ）

For example, O2-, S2-, they can't get electrons anymore, how can they have oxidation?

Addendum:1Liquid oxygen is not oxidizing, is it?! Personally, I think it's just that the cylinder has a good ability to resist pressure.

2。Silver nitrate appears to decompose when exposed to light, so it can only be stored in a brown bottle.

3。Liquid chlorine volatilization can cause damage to the human body and its respiratory tract and should be neutralized in time.

1 A liquid oxygen pressure is high, stored in a steel pressure cylinder; b. Sodium carbonate saturated solution is easy to react with carbon dioxide in the air to form sodium bicarbonate, which must be sealed and stored; c Phenol is slightly soluble in water and soluble in ethanol (alcohol); d Potassium and sodium react violently with water or are called burning in water, and must be extinguished with sand.

2 A concentrated nitric acid is easy to make rubber age; b. Gasoline and kerosene are easy to age rubber; c. Alkaline solution does not use glass plugs, which is easy to be sticked; D silver nitrate is easy to see photodecomposition, so put it in a brown bottle.

3 A chlorine gas density is higher than air density, and should be transferred to higher out; b. Chlorine is soluble in water, soluble in water, easy to neutralize with alkali; c liquid chlorine is volatile, and the diffusion rate after volatilization is not slow, and the toxicity is large; d. Concentrated alkali is easy to burn**.

Liquid oxygen will form a dense oxide film on the inner surface of the cylinder, so it will not further corrode, so the cylinder can be used. And the cylinder can withstand a lot of pressure; b, there is no reason for this, it should be like this.

c Phenol honors alcohol, and the alcohol is non-toxic, so it can be washed; d can only be used with sand. Water reacts with sodium and potassium.

Concentrated nitric acid will corrode the rubber stopper, and glass stoppers should be used; b Do not use rubber stoppers, they are all organic solvents, which may be soluble to rubber stoppers. Moreover, the rubber stopper is too little under pressure, and gasoline and no have strong volatility, so it is not suitable; c. Sodium carbonate and silicon in the glass (I can't remember if it is) will react, and the large surface area of the grinding glass will speed up the reaction, so that the bottle mouth is glued together and difficult to open; d correct.

It should be headwindward; b...c. Liquid chlorine will be extremely strong, and closing doors and windows cannot prevent the entry of chlorine. d, the concentrated caustic soda solution is strongly corrosive, and the soaked mask cannot be bred

A Yes, absolute ethanol is soluble in water and cannot be extracted.

B pair, the Cu(OH)2 suspension reacts with glycerol (polyhydroxy compound) to form a crimson blue solution, which is a characteristic reaction.

c False, the paper chromatography sample point shall not be immersed in the agent, otherwise it will be dissolved in the agent and the paper chromatography will not be possible.

D Yes, the quicklime reacts to acetic acid first, and during distillation, the ionic compounds will not be evaporated, and the ethanol will evaporate.

Note: The original question is a chemistry question in the 2010 Zhejiang paper, and the original question requires the wrong choice.

Select a Ethanol miscible with water.

Glycerol has no aldehyde group.

It cannot be immersed. Ethanol is absorbed by lime, and Ca2+ can absorb alcohols.

D1mol is the amount of matter, its mass = 1mol x molar mass, the mol mass is 28, and the diatomic molecule has 2mol atoms.

The nucleus is made up of protons (with one charge) and neutrons (with no charge).

Then the number of protons should be the number of molecules multiplied by their total charge number, which is 14

d。①m=n*m 。n is the same, is 1molAnd m is 14g molSo the product is the same.

n=n*na

The number of molecules is the same, the number of atoms = the number of molecules multiplied by 2

Total number of protons = number of atoms * 14

1. That is, nitrogen reacts with oxygen in the case of atmospheric discharge to produce nitric oxide

N2+O2=2NO (condition is discharge).

Nitric oxide easily reacts with oxygen to form nitrogen dioxide.

2NO+O2=2NO2 No condition required.

Nitrogen dioxide reacts with water to form nitric acid.

The ratio of the amount of no2 + h2o = hno3 + no (unbalanced) 2, k+ and ca2+ is 2:1

That is, the ratio of the amount of KCl to CaCl2 is 2:1, so the mass fraction is the mass of CaCl2 (CaCl2 mass + KCl mass), and the Cl(-) of 1mol is CaCl2, which corresponds to KCl is 1mol, so the mass of the mixture is 110*

So the answer is:

1. Nitrogen reacts with oxygen and hydrogen in the case of atmospheric discharge to produce nitric oxide and amine

N2+O2=2NO (condition is discharge).

n2 + 3h2 = 2nh3 (condition is discharge).

Nitric oxide easily reacts with oxygen to form nitrogen dioxide.

2NO+O2=2NO2 No condition required.

Nitrogen dioxide reacts with water to form nitric acid.

NO2 + H2O + O2 = HNO3 (unbalanced).

hno3+nh3=nh4no3

The ratio of the amount of matter of 2 K+ to Ca2+ is 2:1

That is, the ratio of the amount of KCl to CaCl2 is 2:1, where the ratio of Cl to the amount of the substance is 1:1

The mixture containing 1mol Cl- contains KCL and the mass of the mixture

1. Nitrogen reacts with oxygen to form nitric oxide Nitric oxide is oxidized by oxygen to nitrogen dioxide. Nitrogen dioxide reacts with water to form nitric acid2

1mol ci has 1 3mol kcl and 1 3mol cacl2 to bring in the amount of the substance is ok, really lz to calculate by yourself... It's useless to write an answer...