Question

State in your own words the law of constant composition.

Short answer

Answer: The mass ratio of hydrogen to oxygen in a water sample is 1/8.

Step-by-step solution

Choose a compound to analyze

Let's choose a common compound to analyze: H2O (water). In water, there are two hydrogen atoms and one oxygen atom.

Find the atomic mass of each element

Now, we need to find the atomic mass of each element in the compound. The atomic mass of hydrogen is approximately 1 amu (atomic mass units), and the atomic mass of oxygen is approximately 16 amu.

Calculate the mass ratio of elements in the compound

To find the mass ratio of elements in the compound, we must calculate the mass of each element in one molecule of the compound. There are two hydrogen atoms in water, so the total mass of hydrogen in one molecule of water is 2 x 1 amu = 2 amu. There is one oxygen atom in water, so its mass is 1 x 16 amu = 16 amu. Now, find the ratio of the mass of hydrogen to the mass of oxygen in one molecule of water: 2 amu (H) / 16 amu (O) = 1/8 H/O

Conclude based on the law of constant composition

Based on the law of constant composition, the mass ratio of hydrogen to oxygen in any sample of water will always be 1/8. This means that in any quantity of water, the mass of hydrogen will always be one-eighth the mass of oxygen, regardless of how the water was prepared or where the water came from.