How to find the mass ratio of each substance in a chemical equation?

We need to start by determining the stoichiometry

Look at the change of ionic valency to determine the stoichiometric number.

For example: KMno4+HCl(concentrated)=KCl+MnCl2+Cl2+H2O

Potassium permanganate + concentrated hydrochloric acid = potassium chloride + manganese dichloride + chlorine + water).

There are two ways to do this.

The first observation method, this is more difficult to master, there is no fixed formula, depending on the personal level, I summarized it myself.

You look at this equation, start with potassium permanganate, the oxygen of potassium permanganate is an even number, so the water of the product must have a number of spouses, that is to say, the HCL in the product must meet the condition of "even H" (I don't understand and I can't do it) Then, since hydrochloric acid is matched with an even number, then Cl must be an even number, look at the product there, to make the total number even, KCL must be accompanied by an even number, try to match a 2 first, then potassium permanganate with 2, so Mn has 2 in the reactant, and manganese dichloride is also matched with 2, Potassium permanganate has 8 oxygen at this time, so water is equipped with 8, so there are 16 hours generated, so HCL with 16, that is, there are 16 CL so chlorine is with 5 (because at this time, manganese dichloride with 2 is 4 chlorine, KCL has 2 chlorine, so chlorine has 10 CL, that is, 5 molecules of chlorine).

How's that, you know?

The second method is the valency method.

Look at the individual compounds in this equation, if you don't know what valency is, forget it.

Let's look at potassium permanganate first, where MN is +7 valence, but in manganese dichloride it is +2 valence.

So mn:+7 +2--- 5 electrons less.

Looking at the chlorine atom again, the valence of potassium chloride and manganese dichloride has not changed, only the chlorine gas has changed from -1 valence to 0 valence.

So cl:-1 0--- one more electron.

We have 5 electrons less Mn in the X molecule, that is, 5x fewer electrons, and 1 more electron in the chlorine gas of the Y molecule, because there are 2 chlorine atoms in a chlorine molecule, so the total number of electrons is increased by 2Y.

That is, 5x=2y, so the simplest ratio of x and y is 2:5

Then put the 2nd generation into the original potassium permanganate or the generated manganese dichloride (manganese's ** or generated), and put the 5th generation into chlorine gas (because only its chlorine valency has changed), and the future should be understood, potassium permanganate, manganese dichloride and chlorine are all out, and the others don't understand you too badly.

In fact, there are many chemical trim methods, which can be searched for the following.

Mass = the amount of the substance multiplied by the relative molecular weight, multiply the coefficient in front of each reactant in the equation by its molecular weight, and then compare to get the mass ratio.

To put it simply, it is related to the amount of a substance involved in a chemical reaction, and it is also related to the amount of the substance, for example, as follows

naohhcl

naclh2o

Then all kinds of substances are involved in one point to one, one to one, and their mass ratio is related to the molecular formula, or the vector of the substance, please see:

naohhcl

NaClH2O Formula Quantity Ratio:

Mass ratio: Same as above.

Another example: na2CO3

CaCl2CaCO3 (precipitate).

2NaCl Formula Quantity Ratio:

Mass ratio: Same as above.

Therefore, to know their mass ratio, you must write the reaction equation correctly, and the trim must be correct. Then according to the formula quantity and the amount of participation, it is the molar ratio. That's it.

The mass ratio of each substance in the equation is the ratio of the product of the test quantity * the previous coefficient of each substance in the equation.

The most basic chemical calculation problems.

In order to. 2h2+o2===2h2o as an example. 2g

How much water does h2 produce at most?

The relative molecular or atomic masses of known and unknown quantities are listed accordingly (note that multiply by the coefficients of the substance in the equation).

Set the generated water xg, column proportion.

2h2+o2===2h2o

2gxgx=18g

The ratio of the mass ratio of the element = (relative atomic mass * number of atoms).

For example, the mass ratio of hydrogen and oxygen in water H2O.

m(h):m(o)=1*2:16=1:8

Another example: the mass ratio of the three elements in potassium chlorate kclo3 = 39::16*3=:48 Another example: the mass ratio of nitrogen and oxygen in a nitrogen oxide is 7:4, and the chemical formula of the oxide is found.

Solution: If the chemical formula of the oxide is NXOY, then the mass ratio of nitrogen to oxygen can be obtained from the chemical formula is 14x:16y

Synopid given to the title: 14x:16y=7:4

Solution: x:y=2:1

The chemical formula is N2O

One substance (compound) is the mass ratio of the element.

Both compounds contain the same element and have the same mass, and the mass ratio of the substance can be found.

If the mass of oxygen in SO2 and SO3 is the same, find the mass ratio of SO2 and SO3.

If the mass of the element is the same, the number of atoms of the element is the same.

3so2---2so3

The mass ratio of SO2 and SO3 is 192:160=6:5

Is it about chemical trembling calculations, and does Zhongshan talk about the mass ratio of each element and the mass fraction of a certain element?

Example: NH4NO3

It contains 3 elements, and the mass ratio is n:h:o=14*2:1*4:16*3=7:1:12

Nitrogen mass fraction = 2n NH4NO3 100% = 14 * 2 80 100% = 35%.

In the chemical equation, the mass between the substances is equal to the ratio of the formula (i.e., the stoichiometric number * relative molecular mass), and the stoichiometric number is the number in front of the balanced chemical formula, such as c+O2 = (ignition) CO2

The mass ratio is 12 to 32 to 44

The coefficient ratio in the equation is the ratio of the quantity of each substance, and the mass ratio of each substance is multiplied by the molar mass of each substance.

Calculate the mass of the element in that substance: put.

The relative atomic mass of the element is multiplied by the number of atoms, e.g., the mass ratio of each element in H2O is calculated.

Solution: Mass of hydrogen element = 1 2 (the relative atomic mass of hydrogen element is 1, and there are two hydrogen elements in H2O) = 2

Mass of the element of oxygen = 16 1 (the relative atomic mass of the element of oxygen is 16, and the element of oxygen in H2O has one) = 16

Mass of the hydrogen element: Mass of the oxygen element = 2:16 = 1:8

The quantity ratio of the substance is equal to the coefficient ratio before the substance.

The mass ratio of each substance is calculated using the relative atomic (molecular) mass, and the previous measurement number must be taken into account.

The mass ratio of each substance in the chemical equation must be multiplied by the number of measurements, and then compared.

Can you give an example? Otherwise, I don't know how to say it.

The ratio of the formula (atomic weight, molecular weight, etc.) between substances is the mass ratio between these substances. For example, 1, the mass ratio of sulfur to oxygen in sulfuric acid (H2SO4) is the atomic weight ratio between them: S 4O = 32 64 = 1 2

l For example 2, in NaOH + HCH = NaCl + H2O, the mass ratio of the four substances is the ratio of the molecular weights between them: 40

How to find the mass ratio of chemistry:Element mass ratio in chemistry = number of atoms multiplied by relative atomic mass ratio. For example, in C2H6O, the number of atoms is greater than C:

h:o=2:6:

1,, relative atomic mass ratio c:h:o=12:

1:16, so the elemental mass ratio of c, h, and o in c2h6o = (2*12):(6*1):

Another example: water H2O, MH:MO2: