Chemistry at the age of 9 will be !!!! Hurry

Don't worry, this knowledge point itself is not difficult, it is very simple. It's just that you haven't learned it yet, and this is the knowledge point of chemistry in the first year of high school.

To put it simply: generally the ionic compounds formed between reactive metals and non-metals are sodium chloride; Non-metals are covalent compounds with each other, such as the water you mentioned. As for what the ionic bond and covalent bond are, it is not the content of junior high school, it may only be involved in the topic, but it will definitely not be tested in the high school entrance examination.

If you want to know more about it, you can do it. Thank you.

You can look at the specific explanation of ionic compounds and covalent compounds, you can find out the difference, and there is a more intuitive way to look at the difference in electronegativity between two elements, generally speaking, if it is greater than it is an ionic compound, and vice versa it is a covalent compound.

Ionic compounds are compounds formed by ionic bonds, which are formed by the transfer of electrons (cations for those who lose electrons and anions for those who gain electrons). That is, the chemical bond formed between the positive and negative ions due to the electrostatic action.

Covalent compounds are compounds formed by covalent bonds composed of shared electrons, covalent bonds are a kind of chemical bonds, two or more atoms use their outer electrons together, and ideally reach a state of electron saturation, thus forming a relatively stable and strong chemical structure called covalent bonds. Unlike ionic bonds, atoms that enter the covalent bond do not show electrical properties outwards because they do not gain or lose electrons. The strength of the covalent bond is stronger than the hydrogen bond and is not much different from the ionic bond or even stronger than the ionic bond.

Common ionic compounds: NaCl, CSCL, Na2O2, NH4Cl base, and most salts! Not all acids, alkalis, salts.

Ionic compounds are compounds that are made up of ionic bonds.

So what is an ionic bond, to put it bluntly, it is the combination of anion and cation into a bond.

NaCl is composed of Na+ and Cl- and is an ionic compound.

Water does not contain ions and is therefore a covalent compound.

Ionic compounds include: strong bases, most salt compounds.

Ionic compounds: acids, very few salts (ALCL3), gases, water, etc.

It is known from the reaction of B and C.

The hydrochloric acid reaction completely produces 672ml of hydrogen, and the converted mass is H2, then the original hydrochloric acid HCL mass is.

The amount of hydrochloric acid is concentrated in mol l

It is known from the reaction of A that the magnesium-aluminum alloy has been completely reacted.

The amount of H2 generated is the mass is.

mg+2hcl=h2+mgcl2

24x 2x

2al+6hcl=3h2+2alcl3

54y 6y

24x+54y=

2x+6y=

The solution is x= y=

mg mass is 24x= mass fraction.

The al mass is 54y= mass fraction.

Let the mass of NaOH in this solution be x g when t

2na+2h2o=h2+2naoh

x/40 x/40

The mass of water participating in the reaction is x 4*18= g

The mass of water after the reaction is (

then there is x+( g

The solution yields x=11 g

The quality of the water g

Solubility of NaOH at T 11 g

Al3+ +3OH- = AL(OH)3, the KSP = of aluminum hydroxide, that is, the concentration of aluminum ions multiplied by the concentration of hydroxide ions is equal to the third power, if you want to make the concentration of aluminum ions in the solution greater than, that is, 1L of dissolved grams of aluminum hydroxide in water, you can calculate that the concentration of hydroxide ions can not be exceeded, from the ion product constant of water is 10 -14, it can be seen that the concentration of hydrogen ions at this time is, that is, pH <, you think, even to dissolve such a point of Al(OH)3 needs pH <, you know that you need strong acid to dissolve aluminum hydroxide. In the same way, you can calculate the maximum pH you need when dissolving how many grams of Al(OH)3 will be dissolved in acidic conditions.

al(oh)3 + oh- = al(oh)4-, which is also written as alo2-+2h2o in secondary school textbooks

Alkalinity is also more or less calculated. It can be calculated with chemical equilibrium.

1.Whether it is soluble in alkali or acid is not only related to the strength of the acid

--It is also related to the acid ionization and basic ionization constants of aluminum hydroxide.

--Aluminum hydroxide will only dissolve if H+ or OH- ionized by acid or base can cause the ionization equilibrium of aluminum hydroxide to shift.

--Two ionization modes of aluminum hydroxide: h+...

alo2-..h2o..

>..al(oh)3..<=>..

al3+..3oh-

--The two ionization equilibrium constants are not the same, and the strength of the acid and base required to move the two ionization equilibrium will not be the same.

2.- Aluminum hydroxide can be dissolved in inorganic strong acids: hydrochloric acid, sulfuric acid, nitric acid.

--Aluminum hydroxide can be dissolved in a certain organic weak acid: acetic acid formic acid.

--Aluminum hydroxide is insoluble in inorganic weak acids: hydrosulfuric acid, carbonate, sulfurous acid.

--Aluminum hydroxide can be dissolved in inorganic strong bases: such as Naoh Koh Ba(OH)2

--Aluminum hydroxide is insoluble in inorganic weak bases: such as ammonia, calcium hydroxide, magnesium hydroxide, iron hydroxide.

Just remember!!

I don't know... I only know that it is in the diagonal of the periodic table, it is an amphoteric element, aluminum hydroxide is also amphoteric hydroxide, the landlord's problem may involve the law of orbit and sublayers and other problems, at least the first year of high school does not need to be considered... If the landlord wants to take chemistry in the second year of high school, it will probably be the content of elective four (Jiangsu).

Al(OH)3 is amphoteric and can be used as both a base and an acid.

It is both a weak acid and a weak base, which is very weird, haha, so it can only react with strong acids and strong bases.

4GC and 8GD are generated, and no B substance is left, then the mass of A participating in the reaction is 4G+8G-10G=2G

Then the mass ratio of the two substances when they react is 2g:10g=1:5 to choose b

B is fully reflected because B has no leftover, and C + D is 12 grams, so A reacts 2 grams so 1:5

5 to 1, the mass of mass balance A is 4 plus 8 minus 10 is 2, and 2 to 10 is 1 to 5. The answer is b

According to the law of mass conservation, we can know that the total mass of A and B participating in the reaction is 12 grams, and the 10 grams of B participating in the reaction have all been reacted, and we can know that the mass of A in the reaction is 2 grams, and the mass ratio of the two substances when reacting is 1:5

Conservation of mass.

Generate 12 g of C+D

There is a 12 gram of A+B reaction.

b = 10 then a = 12 - 10 = 2

a b = 1 out of 5 choose b

A false, carbon monoxide reduces copper oxide to produce carbon dioxide, and hydrogen reduces copper oxide to produce water, both of which are non-toxic.

B false, the reaction of carbon monoxide with copper oxide is not a displacement reaction (no elemental element appears).

c is correct, and both produce red solid copper.

d false, the valency of oxygen has never changed, it is -2.

The gases produced after the CA reaction are toxic – CO2 is non-toxic.

B reaction types are all displacement reactions – CO is not.

c reacts to produce a red solid – yes, because of copper.

The valency of each element has changed before and after the reaction – some have not changed.

A C ten 2cuo = high temperature = 2 cu ten CO2

C02 is non-toxic.

b co+cuo=△=cu+co2↑

Because CO is not elemental, this reaction is not a displacement reaction.

c True Under certain conditions, charcoal, carbon monoxide, and hydrogen can reduce copper oxide, and copper is purple-red.

Error Although Cu decreases from +2 valence to O-valence in each reaction (elemental valency is 0), the valency of oxygen is always -2 valence.

The carbon dioxide generated by the reaction of CO and Cuo is non-toxic, B is wrong, not a displacement reaction, and the elements described by D include oxygen, and oxygen has always been -2 valence, so choose C

c can have a reduction reaction with copper oxide!!

A false, hydrogen reduces copper oxide to produce water, which is non-toxic.

B false, the reaction of carbon monoxide with copper oxide is not a displacement reaction.

c is correct, and both produce red solid copper.

d false, the valency of oxygen has never changed, it is -2.

The carbon content is 48%.

Then the mass of element c is 10 48%=

And these C's are all in CO2.

After the CO2 reaction, C is all changed to CaCO3.

So the mass of c in caco3 is.

then c--caco3

x solution yields x=40g

So the white precipitate is 40g

According to the conservation of carbon, the amount of carbon in the final precipitation of calcium carbonate is equal to the amount of carbon in the gas mixture before combustion.

1. Relative molecular mass: 12 6 1 8 16 6 1762, mass ratio is relative atomic mass ratio: 12 6:1 8:16 6 72:8:96 9:1:12

3，352×8/176＝16g

The density of 2% copper sulphate solution is known, Q:

1) How many grams of CuSO4·5H2O crystals are needed to prepare 500ml of this solution?

Crystal XG is required

160x/250=500*

x=2) What is the concentration of the substance in the resulting solution?

According to the conversion formula.

c=1000pw/m=1000*

Impure anhydrous sodium carbonate (the impurities contained in it do not react with acid), add it to the sulfuric acid solution, heat, and then add 40ml of caustic soda solution, just neutralization, Q:

1) How many milliliters of carbon dioxide can be obtained in the above process

na2co3

h2so4na2so4

h2oco2

h2so42naoh

na2so4

2H2O sulfuric acid, NaOH, the reaction of sulfuric acid, i.e. sulfuric acid that reacts with Na2CO3, i.e., the hole is destroyed, and CO2 is generated, i.e.

2) Find the purity of anhydrous sodium carbonate.

The reaction of Na2CO3 is, i.e., purity,