The title of the chapter on the quantity of chemical substances in the first year of high school

HCL is a solute, the mass is 73 grams, and the solvent is 10mol of water and 180 grams, so the mass fraction is 73 253*100%.

H+ in water comes entirely from HCl ionization, and the ionization of the molecule is negligible, so it is 1:10

My process may not be standardized, but it is purely for the convenience of understanding ......1: Na+, 1mol, that is, there is.

Since the chemical formula of sodium sulfate "Na2SO4", the ratio of the number of sodium ions to sulfate ions should be 2:1

In this way, there are sulfate ions.

At the same time, the ratio of the number of sulfate ions to the number of sodium sulfate molecules should be 1:1, so there are sodium sulfate molecules.

Because the relative molecular mass of sodium sulfate is "142g mol".

So the mass corresponding to sodium sulfate is ".

2: It is known that the relative atomic mass of Fe is 56, then the molar mass of iron is 56g mol1mol of iron is 56g

1mol of iron is still an iron atom, so the corresponding iron atom is 56g, so it's easy to forget one.

About yes (this number is very large, maybe I didn't calculate it correctly, it is recommended to trouble to calculate it again) 3: This question seems to be very popular, I also have it on my homework, but I think this question is very strange, and I look forward to the master to solve the puzzle I personally think that this is the case:

1 C12AG, then NA is NA*AG

Since na is 1mol

Then the molar mass of C12 is Na*AG mol, and then what about it, because the molar mass is numerically equal to the relative particle mass, the relative atomic mass of C12 can be deduced as.

na*a", the relative atomic mass of the r atom can be deduced as "na*b" according to this

Damn, this number is even more cuppy.

An element contains an atom.

An atom is exactly "1 mol atom", so the relative atomic mass of this element is because the molar mass is numerically equal to the relative particle mass.

So the relative atomic mass of this element should be.

N(Na2SO4)=71 (23*2+32+16*4)mol=SoN(Na+)= *2mol=1molN(SO4-)

If you don't understand, please ask.

The sodium ion is 1mol and the sulfate is.

That's okay, I'm so happy to be reading now.

Molecule of nitrogen =

Atom = the amount of substance of a molecule of a certain elemental rx =

The number of atoms is the same.

x = molar mass of 3rx =

r relative atomic mass = 48 3 = 16

n(n2)=, containing n atoms:

is also containing atoms, then the atomic weight is:; is the o element;

x = 3, ozone.

The number of N2 molecules is. The number of atoms is.

So RX is there. The number of atoms is. That is, there are 3 atoms in a molecule. Then x=3 relative atomic mass=

I guess it's ozone.

The amount of nitrogen is divided by 28g mol of nitrogen in the molar of nitrogen, which is equal to, contains nitrogen atoms, and the number of atoms of r is the same as the number of nitrogen atoms, then also, the molar mass of r is , the relative atomic mass of r is 16, and the ratio of the number of molecules of n2 to rx is 3:2, and the amount of n2 is , then the amount of rx is the amount of matter, and the number of r atoms is, then x = 3

16 3 The number of molecules of nitrogen, the number of atoms, then the number of molecules of rx, the number of atoms, therefore, the relative molecular mass is 48, x = 3, so the relative atomic mass of r is 16, and rx is ozone.

The number of atoms of nitrogen is the number of molecules, so the number of atoms of a certain element Rx is also the number of molecules, from which it is deduced that the relative atomic mass of x=3 and r is 16

Remember Avogadro's constant. na= The title is dividing by the amount of matter.

Mass = amount of matter * molar mass.

The number of protons is equal to the atomic number.

1. The first empty you have already counted.

2 oh- The quality is.

3 A o contains protons 8 h contains protons 1 of 9

So 9 4 o contains electrons 8 h contains electrons 1 because it is oh- plus one more for a total of 10.

So 10

5 Calculation: Same mass as NH3 for most moles Suppose the amount of NH3 substance is amol

a×17= a=

6 Calculation: The number of ions contained in the same number as how many Na+ (in fact, the same amount of matter) is assumed to be B g

b÷23= b=

In fact, the first question does not need to be calculated, because the molecular weight of NH3 is 17 and the molecular weight of OH- is also 17, so it is the same.

I don't know how to ask again, I'm very patient!

This is a question and answer question, not a calculation question, how to write the process--

1) 3H2SO4 6mol H 12mol O H2SO4 Molecular number 3*

2) mol

3） 9g4)(5)2mol 46g 12g 1mol 3mol 48g

The key to this question is that this gas is dissolved in water, what is the solution solute. Or this gas. The amount of gaseous substances (calculated according to the original gas) is v, and only the volume of the solution is required.

Let's calculate the volume. Now that you know the density, you need to find the quality of the solution. The solution is made up of two parts.

Gas with water. The gas mass is vm 100gSo find the volume.

The answer can be found by using the amount of gaseous substance and the volume of the solution (note that the volume is reduced to l).

Well, I've done the math, and it's the answer. So you'd better do the math and experience the solution to this kind of problem.

First, it is determined that the reddest product is a mixture of Na2CO3 and NaHCO3, and set Xmol Na2CO3 and YmolNaHCO3 to be conserved according to C: x+y=

Conservation according to na: 2x+y=1

Solution: x= y=

Answer: The amount concentration of the substance of Na2CO3 is:

The concentration of the substance NaHCO3 is:

The amount of CO2 (STP) = , 2NaOH + CO2 ====Na2CO3 + H2O

Remaining, Na2CO3 +CO2 +H2O ===2NaHCO3

So the amount of substances containing Na2CO3 in the solution = , the amount of substances containing NaHCO3 =

The ratio of the amount concentration of Na2CO3 and NaHCO3 substances in the solution = the ratio of the amount of solute =: 3

n(co2)=

n(naoh)=

Let the generated NaHCO3 be xmol and Na2CO3 be ymolx+2y=1mol

x+y=x= y=

Because the concentration ratio is equal to the quantity ratio of the substance.

Ratio of the amount and concentration of solute in the resulting solution: 1

It's just proportionality

The relative molecular mass of ammonia is 17, the relative molecular mass of air is 29, and the relative molecular mass of the gas inside the bottle: 2

Therefore, the volume ratio of ammonia to air is x:y17x+29y) :x+y) =19

The solution is x:y = 5:1

Ammonia is soluble in water, while air is insoluble, so.

The volume of the liquid level rise in the flask is 5 6