what is law of constant proportion
Answers
Answer:
The law of constant proportion was given by Joseph Louis proust. It says that in a chemical substance (compound) elements are always present in definite proportion by mass. For example: In a compound such as water the ratio of mass of hydrogen to the mass of oxygen is always
Despite being a building block in the development of chemistry, the law of constant proportions does not hold true for all chemical compounds. Some exceptions to this law are listed below.
Some non-stoichiometric compounds have varying compositions of elements between samples. These compounds obey the law of multiple proportions instead.
One such example is wustite, an oxide of iron with the chemical formula FeO. The ratio of iron and oxygen atoms can range from 0.83:1 to 0.95:1.
This is caused by the crystallographic vacancies in the samples caused by a disorderly arrangement of atoms.
Various samples of a compound may vary in the isotopic composition of its constituent elements. This can lead to fluctuations in the mass ratios.
The differences in the mass ratios between samples are very useful in the process of geochemical dating, due to the preferential concentration of isotopes in many deep Earth and crustal processes.
This also occurs in many oceanic, atmospheric and even astronomical processes. Despite the effects being quite small, the challenges in the measurement of the effects have been overcome by modern instrumentation.
Since natural polymers can vary in their compositions, various samples can show different mass proportions.