Please teach the chemistry question Please, help me do this chemistry question I m on the exam Pleas

The mass of CO2 generated is: 120 + 200-276 = 44 grams.

Let the mass of CaCO3 in limestone be X

CaCO3 + 2HCl = = CaCl2 + CO2 + H2OX --- 44 grams.

x = 100 grams.

The purity of limestone is: 100 120==

CaCO3 + 2HCl = = = CaCl2 + H2O + CO2120 + 200 = 320 grams.

Now it's only 276 grams, and the reduction is the weight of CO2 = 320-276 = 44 grams.

For every 100 grams of limestone reacted according to the chemical reaction formula, 44 grams of CO2 were generated.

So in the original limestone, the weight of caco3 is 100 grams.

Its purity = 100 120 * 100% =

From the law of conservation of mass, it can be seen that the total mass of matter before the reaction is equal to the total mass of the substance after the reaction.

CaCO3 + 2HCl = CaCl2 + H2O + CO2, CO2 will diffuse into the air after reaction.

120 g of limestone + 200 g of dilute hydrochloric acid = 276 g of the remaining substance + mass of CO2.

Mass of CO2 = 44g

Let the mass of calcium carbonate be x

caco3+2hcl=cacl2+h2o+co2x 44g100/x=44/44g

x=100*44g/44

x=100g

Purity of limestone 100g 120g*100%=

The reduction of 120 + 200-276 = 44g is CO2

CaCO3+2HCl=CaCl2+H2O+CO2X 44g: According to the equation, the mass of CaCO3 is (100 44)*44=100g

Purity: (100 120)*100%=

The mass of CO2 generated is 120 + 200-276 = 44 g;

Let the purity of limestone be x:

caco3+2hcl=cacl2+h2o+co2120g*x 44g

Solution: x=

2hcl+caco3===cacl2+co2+h2ox 44g

x 44gx=100g100g

120g A: The purity of raw limestone is.

It is possible from the title: carbon dioxide is 44g

caco3---co2

x 44100:44=x:44

x=100g

Answer--- Yes.

...Think about it yourself... Exams are still up to you...

(1) A: Solubility decreases with the increase of temperature, such as: Ca(OH)2

b: Solubility increases significantly with the increase of temperature, such as kno3

C: The solubility does not change significantly with the increase of temperature, such as NaCl

2) a>c>b Raise the temperature and lower the temperature.

3) Where is point m? Is it above the A-curve and below the B-curve? If yes, answer as follows:

Saturated, unsaturated, saturated.

If not, think for yourself, it's simple.

4) A b solubility 40

5) b a6) 16g 18g 18g unsaturated saturated saturated.

7) Heating up crystallization (or evaporation crystallization) Evaporation crystallization.

8) Cooling crystallization Evaporation crystallization.

9) Add an appropriate amount of substance C to the solution, heat the solution, and evaporate the solvent at a constant temperature.

Whew,Finally answered.,I'm tired.,Although there are a lot of questions.,But it's not too difficult to return.,It's better to do it yourself in the future.。

By the way, the increase in the solubility of a substance mentioned in question (2) is actually unscientific, as long as the temperature does not change, the solubility cannot be changed.

Oh no, I just said that in question (1), besides, isn't the way to change solubility is to change the temperature? lz ignored my words, okay, it may be a smoke for a while.

By the way, I'm not sure about the first empty answer to question (7), theoretically Ca(OH)2 type substances, from their solution to get solute, are all by cooling crystallization, but I think evaporation crystallization is not impossible, because cooling crystallization can not get as much solute as possible.

(1) A: The solubility decreases with the higher the temperature B: The solubility increases rapidly with the increase of temperature, and C: The solubility increases steadily with the increase of temperature.

2) a>c>b reduce the temperature and increase the temperature (3) a saturated b unsaturated c saturated.

4) A and B are the same, both are 40

5) Up to b without a

6) 16g 18g 18g unsaturated, saturated, saturated, (7) evaporative, cooled.

8) The solution is heated to T3 first, and then cooled to T2, and the crystalline solution of B is cooled below T1.

9) Heat solution A.

CaCl2+K2CO3==CaCO3+2KCL can be seen from the "when the mass of K2CO3 solution is 30g, when the mass of precipitation solution is 40g, and the precipitation is 2g", all calcium corresponds to 2g of calcium carbonate, so it contains brigade calcium, and calcium chloride is.

2HCl+K2CO3==2KCl+H2O+CO2 From "when the mass of K2CO3 solution is 20g, there is a small amount of precipitation", it can be seen that 20g of potassium carbonate solution and hydrochloric acid are just completely reacted (the amount of precipitation is small and negligible), and the potassium carbonate of the reaction is 20g*, and the hydrochloric acid of the reaction is there.

The remaining solids are KCL, K2CO3 and CaCO3, of which 2g of calcium carbonate, a total of 40g of potassium carbonate is added, which reacts with hydrochloric acid, and reacts with calcium chloride 2g 100*138=, so there is no left, there is wrong.

The oxidizing nature of iodate is greater than that of iodine element, therefore.

io3- +5i- +6h+ =3i2 +h2o

Iodate + iodine + hydrogen = iodine + water.

For similar topics in chemistry, look for knowledge points in textbooks. Take potassium iodate, for example. The corresponding textbook should be potassium chlorate. Potassium chlorate is decomposed by heat. So a is incorrect.

[Sufficient amount of dilute hydrochloric acid] Fe mixed with Zn completely reacts H2

Fe + 2]HCl ===FeCl2 + H2 Zn + 2]HCl ===ZNcl2 + H2 Let the amount of iron species be a and zinc be b

a+b=56a+65b=

The solution is a= b=

m(fe)=

m(zn)=

Do it with conservation of electrons of gain and loss. fe+2hcl=fecl2+h2,zn+2hcl=zncl2+h2.+2 and +2 respectively. Let the iron be xmol, zinc, 56x+65y=. x=,y=

Step 1:

List the chemical equation first, Zn+2HCl=ZnCl2+H265 1N x and then cross-multiply to obtain:

n=65x

Sulfuric acid reacts with NH3. Caustic soda with CO2HCl. There is の because there is no o2 because of a change of colorOtherwise, it will react.