Question

A 17g sample of H2O2 was decomposed to yield 1g of H2 and 16g of O2 An unknown sample containing only H and O was decomposed to yeild 2g of H2 and 16 g of O2. The formula for the unknown sample is:

Answer 1

Step-by-step explanation:

Our
`H_2O_2` sample yielded 1g of
`H_2` and 16g of
`O_2`, but our unknown sample yielded 2 times as much
`H_2` for the same amount of
`O_2`.

What does this mean? that the H:O proportion for the unknown sample is twice the H:O proportion for the
`H_2O_2` sample.

What is the H:O proportion for the
`H_2O_2` sample? As we can see from its formula, it's 1:1, therefore the proportion for the unknown formula must be 2:1.

That means, two H atoms for every O atom. We could write that as:
`H_2O` and you should recognize that formula, for it is one of the most common compounds on earth, Water.