# Add 50ml 2mol / L H2SO4 solution to the mixture of Fe3O4 and Fe in a certain amount, and just dissolve the mixture completely under certain conditions, releasing 448ml (under standard conditions) gas. Add KSCN solution to the resulting solution, and there is no red. Then fully react with the mixture of the same mass with sufficient CO at high temperature, and what is the mass of iron?

## Add 50ml 2mol / L H2SO4 solution to the mixture of Fe3O4 and Fe in a certain amount, and just dissolve the mixture completely under certain conditions, releasing 448ml (under standard conditions) gas. Add KSCN solution to the resulting solution, and there is no red. Then fully react with the mixture of the same mass with sufficient CO at high temperature, and what is the mass of iron?

[the idea of solving this problem is to determine the quality of the final reduced Fe, then determine the amount of Fe element in the mixture] the amount of sulfuric acid participating in the reaction n (H2SO4) = 0.05 * 2 = 0.10 (mol) from the relationship Fe ~ H2SO4 ~ H2, it is known that n (H2) = 0.448 / 22.4 = 0.02 (mol), so N1 in the first part

### Ask a senior one chemistry calculation question, which needs to be explained in detail Prepare 1000ml of 1.00mol/l hydrochloric acid (density about 1.00g/cm3) with concentrated hydrochloric acid with density of 1.19g/cm3 and mass fraction of 36.5%? Please explain in detail. OK, add 10

The amount of HCl remained unchanged before and after dilution
Amount of substance before dilution = density * Volume * mass fraction / molar mass
Amount of substance after dilution = concentration * Volume
If the two are equal, the volume can be solved, and finally the liter can be converted into ml

### Put 6.5g zinc into a sufficient amount of dilute sulfuric acid for full reaction to obtain 80ml solution with a density of 1.25g/ml. Calculate the amount, concentration and mass fraction of zinc sulfate in the solution? It seems very simple, but I don't know how to write it 25mol/ml 16.1% Can you write down the detailed process Just tell me what I think

6.5g zinc is 0.1mol zinc. If there is 0.1mol zinc, then there is 0.1mol zinc sulfate. The volume of the solution is 0.08l, and the quantity and concentration of zinc sulfate is 0.1/0.08. If there is 0.1mol zinc, then there is 0.1mol zinc sulfate. The mass fraction is the mass ratio of zinc sulfate to the total mass of the solution, which is 125g / mol * 0.1/1.25g/ml * 0.08l

### If the electrolyte is saturated sodium chloride solution, the electrode reaction formula of the cathode in the electrolytic cell is___________________

First of all, explain my point of view: what are the two upstairs doing   LZ is the cathode electrode reaction formula for electrolysis of saturated sodium chloride solution!
4H+  +  4e-  =  2H2

### Senior one chemistry problem, for detailed explanation Dilute sulfuric acid reacts with excess zinc powder. At a certain temperature, in order to alleviate the reaction rate without affecting the total amount of hydrogen generated, an appropriate amount of sodium acetate solid can be added to the reaction solution. Why?

Sulfuric acid can react with sodium acetate to produce sodium sulfate and acetic acid. This reaction is a double decomposition reaction. Its essence is to prepare weak acid from strong acid. Completely ionized sulfuric acid produces substances that are difficult to ionize
After the formation of weak acid, the concentration of hydrogen ions in the solution decreases, but the total amount of hydrogen ions remains unchanged. Due to the decrease of hydrogen ion concentration, the reaction rate slows down, while the total amount of hydrogen ions remains unchanged

### Put starch and NaCl solution into semi permeable membrane bag and immerse in distilled water for dialysis. Try to answer: (1) The experimental method to prove that starch does not penetrate the semipermeable membrane and Cl ion has penetrated the semipermeable membrane is__________________ (2) The test method to prove that starch and NaCl have been completely separated is_________________________

Take a small amount of liquid inside and outside the bag and drip iodine solution,
Then take a small amount of liquid inside and outside the bag, add silver nitrate and nitric acid
The liquid in the bag was added with silver nitrate and nitric acid, and there was no precipitation