quiz 6 - 3sec iron properties .

One of the following equations, iron III oxide acts as a base

• Fe2O3 + CO →(400–700c) 2FeO + CO2

• Fe2O3 + 6HCl →(conc.) 2FeCl3 + 3H2O

• Fe2O3 +3H2 →(700c) 2Fe + 3H2O

• 3Fe2O3 + CO →(230–300c) 2Fe3O4 + CO2

Which of the following alloys prevent the slipping of the layers over of each other?

• Steel

• Cementite

• Duer alumin

• Stainless steel

The opposite figure is for one of iron oxides. Which of the following statements about this compounds is correct?

• Oxidation number of iron in this compound is+2

• it is reduced by CO at a temperature higher than 700°C forming iron

• The percentage of iron in it increases by roasting

• It can be obtained from the reaction of FeO with dilute H₂SO₄

When Iron III oxide is heated in air , the percentage of oxygen ...

• Increases

• decreases

• equal

• slightly decreases

.......can be decomposed thermally

• FeSO4

• Fe(OH)₃

• Fe₃O₄

• All the previous

No industrial products made of pure iron , the reason is all the following except…

• pure iron is soft

• pure iron is malleable

• pure iron is ductile

• pure iron has low melting point

When we heat a mixture of (FeO, Fe₂O₃) in air, the final product is …

• FeO

• Fe₂O₃

• Fe₃O₄

• FeCl2

An alloy, the ratio between the sizes of its component elements is 1:1. This alloy is …

• Steel

• stainless steel

• Yellow copper

• Duer alumin

All the following methods for preparing red iron oxide except …

• Oxidizing black iron oxide

• The reaction of red hot iron with air

• Heating iron (II) oxalate in air

• The thermal decomposition of iron (III) hydroxide

An iron oxide is formed by heating (in absence of air) the salt which is produced from heating iron (II) carbonate with …

• Acetic acid

• Oxalic acid

• Formic acid

• Benzoic acid