## 13 g of zinc reacts with 100 g of dilute sulfuric acid to find: (1) the mass of oxygen produced (2) the mass fraction of dilute sulfuric acid

Zn and dilute sulfuric acid can not generate oxygen, but only hydrogen

So how to calculate the mass of hydrogen produced?

Because it is just a complete reaction, we do not know how much sulfuric acid there is in the dilute sulfuric acid solution, so it should be calculated according to the mass of Zn

Write the reaction equation

Zn + H2SO4 = ZnSO4 + H2

65 98 2

13 x y

So 65 / 13 = 98 / x = 2 / Y

The solution is x = 19.6g and y = 0.4g

Therefore, the mass of hydrogen is 0.4g

The mass fraction of dilute sulfuric acid is (19.6 / 100) * 100% = 19.6%

### 13 g of zinc reacts with 100 g of dilute sulfuric acid exactly to obtain: 1. Mass of solute and solvent in dilute sulfuric acid. 2. Mass of solution obtained after reaction and solute and solvent in the obtained solution. 3. Mass fraction of solute in dilute sulfuric acid. 4. Mass fraction of solute in solution obtained after reaction

65 98 161 213 x y ZX = 19.6g, y = 32.2g, z = 0.4g \ x0d the mass of solute in dilute sulfuric acid is 19.6g, the mass of solvent is 100-19.6 = 80.4g \ x0d the mass of solution after reaction is 100 + 13-0.4 = 112.6g, the mass of solvent is 100-0.4 = 99.6g \ x0d the mass fraction of solute in dilute sulfuric acid is 19.6 / 100 * 100% = 19.6%

### How many grams of sucrose need to be added to concentrate 100 grams of sucrose solution with a mass fraction of 10% into 20% sucrose solution? To process Oh! Be more detailed!

The mass of sucrose is 100g * 10% = 10g. If the mass of sucrose to be added is mg, then (M + 10) / (100 + m) = 20%, the solution is m = 12.5, then 12.5g of sucrose needs to be added

### How many grams of sucrose is needed to increase the mass fraction of sucrose in 100 kg of 10% sucrose solution to 20%? How many grams of water do you need to evaporate?

If the mass fraction is increased to 20%, sucrose x is required

Then: 100X10% + x = 20% (100 + x)

x=12.5g

Set the required evaporation water as y

100X10%=20%（100-y）

y=50g

A brief answer

### How many grams of sucrose solution with mass fraction of 40% is needed to prepare 100g sucrose solution with mass fraction of 10%? How many grams of water do you need to add?

25g sucrose solution with mass fraction of 40% is required, and 75g water is required

Let the mass of sucrose solution requiring 40% be X

100*10%=40%x

x=25g

Mass of water required = 100-25 = 75g

### In order to change 100 grams of sucrose solution with 10% solute mass fraction into sucrose solution with 40% solute mass fraction, it is necessary to continue to dissolve sucrose into the original solution ___ Gram; If you want to change the original solution into a sucrose solution with a solute mass fraction of 5%, add water_____ gram

If necessary, sucrose XG needs to be dissolved in the original solution

100*10%+x=(100+x)*40%

x=50g

Let's add y grams of water

100*10%=(100+y)*5%

y=100g

To change 100 grams of sucrose solution with 10% solute mass fraction into sucrose solution with 40% solute mass fraction, continue to dissolve sucrose 50 into the original solution___ Gram; If you want to change the original solution into a sucrose solution with a solute mass fraction of 5%, add water_ 100____ gram