Question

write the anhydrous form of each of the following:
Ca(OH)2
H2SO4
Fe(OH)2
Fe(OH)3
CaC4H4O6
C5H10O2

Answer 1

An anhydride is the chemical in which water react forming a base.
So what could we do with the first one?

Answer 2

give one to Ca?

Answer 3

Let me rephase the question write what should stand on the ? in the following reaction;
? + H2O -> Ca(OH)2

Answer 4

2Ca

Answer 5

or CA-

Answer 6

Naa not quite. Let me give you the first one:
CaO + H2O -> Ca(OH)2

Answer 7

So the anhydride is calciumoxid (CaO)

Answer 8

Try the next one:
? + H2O -> H2SO4

Answer 9

SO2+H20 for the second one?

Answer 10

Not SO2 you are to low on oxygen. try again.

Answer 11

SO4

Answer 12

SO3 ;)

Answer 13

SO3+H2O

Answer 14

Exactly! so sulfate-trioxid is the anhydride to sulfuric acid

Answer 15

FeO+H2O for nest one? ;D

Answer 16

Perfect!
Next one is a bit harder.

Answer 17

Fe2+HO

Answer 18

Not quite. I help you a bit on this one and then I got to go (think you got the hang of it)
3 H2O + ? -> 2 Fe(OH)3

Answer 19

What is ?

Answer 20

Fe6

Answer 21

6fe

Answer 22

Arrr think:
We need two ion on both sides so it most be Fe2 something. now we see the hydrogen on both sides are fine (6 on both sides) what is missing is 3 oxygen. So the anhydride is:
Fe2O3

Answer 23

Thank you ;D

Answer 24

Good luck with the rest. Just set up the equations like I do and then find what ? is. :)

Answer 25

okay working on it right now :D

Answer 26

Ca2C4H4O4
C5H7O5