## 25g limestone containing 20% impurities fully reacts with 100g sufficient dilute hydrochloric acid (impurities do not participate in the reaction) Requirements: 1. What is the mass of carbon dioxide generated? 2. How many kilograms of calcium chloride are generated?

If it contains 20% impurities, the content of CaCO3 is 80%, and its mass is 25 * 80% = 20g,

Set

CaCO3+2HCl=CaCl2+H2O+CO2↑

100 111 44

20g Y X

Column ratio, solution,

X = 8.8 g

Y = 22.2g

Answer: the mass of CO2 is 8.8g and the mass of calcium chloride is 22.2g

### In the laboratory, 25g limestone containing 20% impurities is prepared by reacting with 100g dilute hydrochloric acid 1. How many grams of carbon dioxide gas can be produced? 2. What is the volume of these carbon dioxide gases? 3. What is the mass fraction of 100g hydrochloric acid solute

In limestone, the mass fire of calcium carbonate is 25g * 80% = 20g. Suppose that the mass of carbon dioxide is x, the mass of hydrogen chloride in the reaction is ycaco3 + 2HCl = = CaCl2 + H2O + co2100 73 4420g y XX = 8.8g y = 14.6g, and the volume of carbon dioxide is the mass divided by the density of carbon dioxide, then the problem is lack of density

### 73g hydrochloric acid with a mass fraction of 20% reacts exactly with a certain mass of sodium hydroxide solution, and the mass fraction of solute in the generated sodium chloride solution is 13.52% Please calculate the mass of sodium chloride solution

Let the mass of sodium chloride solution be X

NaOH+HCl=NaCl+H2O

73 58.5

73g*20% 13.52%x

73/14.6=58.5/13.52%x

x=86.5g

Answer: the mass of sodium chloride solution is 86.5g

### 40 grams of sodium hydroxide solution with a mass fraction of 20% reacts exactly with a certain mass of dilute hydrochloric acid. What is the mass of sodium chloride? If dilute hydrochloric acid is used If the mass of sodium chloride is 60 g, what is the mass fraction of sodium chloride solution?

Resolution:

When 40 g of sodium hydroxide solution with a mass fraction of 20%, the solute sodium hydroxide is 8 g, i.e. 0.2 mol

If it reacts exactly with hydrochloric acid

Then the generated sodium chloride is 0.2mol, that is, 11.7g

Then the required hydrogen chloride is o.2mol, that is, 7.3 G

When the dilute hydrochloric acid is 60g, the mass of the solution after reaction is 40 + 60 = 100g

Mass fraction of the obtained sodium chloride solution = 7.3/100 = 7.3%

### 100g dilute hydrochloric acid reacts completely with 100g 16% sodium hydroxide solution to calculate the mass fraction of dilute hydrochloric acid solution

HCl ------NaOH

36.5 40

100*X 100*16%

X=14.2%

Mass fraction 14.2%

### 12.5g limestone is put into 100g dilute hydrochloric acid to completely react and release 4.4g gas. What is the mass fraction of calcium carbonate in limestone?

Suppose that limestone contains x g calcium carbonate

CaCO3+2HCl==CaCl2+H2O+CO2↑

100：x=44：：4.4g x=10g

10/12.5=80％