Question

A metal oxide contain 40% oxygen by mass, the % of hydrogen in metal hydride will be

Answer 1

In the event that your oxide contains 60% metal than it has 40% oxygen.

Taking a gander at 100 gram of the oxide: 40 gram oxygen which is 40/16 = 2.5 mole O

Oxide implies the O has taken in 2 electrons, so add up to admission 5 mole electrons

These more likely than not originated from the 60 gram metal.

So 60 gram metal gave 5 mole electrons, and as indicated by the definition the identical weight will be 60/5 = 12

Answer 2

This amounts to finding the atomic weight of the metal and the charge on the cation (in effect identifying the metal itself).

I didn't know how to do this, so I looked up the solution. It goes as follows.

Solution

Assume the oxide has the formula MO. Let the atomic weight of M be x Then

16x+16=40100

Simplifying and solving for x yields

x=24

Thus the metal is magnesium and the equivalent weight is 12.

My problem is, how can we assume that the metallic oxide has the formula MO? For all we know, the metallic oxide may be M2O or M2O3. In fact, if we assume the latter formula we get

482x+48=40100