. A chemist decomposes several samples of water into hydrogen and oxygen and weighs (or

Problem 22

A chemist decomposes several samples of water into hydrogen and oxygen and weighs (or more correctly measures the mass of) the hydrogen and the oxygen obtained. The results are tabulated as follows.

(a) Summarize these observations in a short statement.

Next, the chemist decomposes several samples of carbon dioxide into carbon and oxygen. The results are tabulated as follows.

(b) Summarize these observations in a short statement.

(c) Formulate a law from the observations in (a)and (b).

(d) Formulate a theory that might explain your lawin (c)

                                                               Step by Step Solution

Step 1 of 4

a)

Let us take one molecule of water.

The molecular formula of the water molecule is .

From the molecular formula, we can say that one molecule of water contains one atom of Oxygen and two atoms of hydrogen.

The atomic mass of Oxygen is 16 u.

The atomic mass of Hydrogen is 1 u.

Let’s calculate the ratio of masses of oxygen and hydrogen present in one molecule:

So, the ratio is H:O = 1:8.

Now let’s calculate the same ratio for all the samples.

As we can see the ratio is the same for all the samples and it does not depend on anything.

We can summarise this experiment as:

“The chemical composition of a molecule is fixed and a compound can be formed by the constituent atoms taken in a fixed proportion only. It does not change with time, place or circumstances. If the proportion is changed, the chemical property will also be different and it will not produce the same compound”.