Students in the chemistry interest group want to determine the mass fraction of iron oxide in hematite. ⅰ. A student took a certain amount of hematite powder and excessive charcoal.

(1) Vent the air in the equipment. (2) NaOH solution in B will be sucked back into A to form a hard glass tube.

Rupture (or reoxidation of generated iron) (3) Small.

Test and analysis: (1) When reducing iron oxide with carbon monoxide, the air in the device should be exhausted first to prevent explosion;

(2) After the reaction, nitrogen should be stopped after the test tube is cooled to prevent the generated iron from being oxidized again;

(3) Because the reaction between carbon and iron oxide may also produce carbon monoxide, which will not be absorbed, the determined mass fraction of iron oxide will be small.

The mass ratio of iron oxide to ferric chloride can be used to calculate the mass of ferric chloride.

Solution: Let the mass of FeCl 3 produced by the reaction be X.

Fe 2 O 3 +6HCl═2FeCl 3 +3H 2 O？

160325

10g×80%？ x

x =(325×8g)/ 160 = 16.25g？

Mass fraction of FeCl _ 3 in solution =16.25g/(154.5g+8g) ×100% =10%?

A: The mass fraction of ferric chloride in the solution after the reaction is 10% respectively.