It means that different compounds composed of the same elements have their own unique proportion of those elements. For example, both water (H2O) and hydrogen peroxide (H2O2) are composed of hydrogen and oxygen. However, the proportion of hydrogen to oxygen in water is 2 to 1, and the proportion of hydrogen to oxygen in hydrogen peroxide is 1 to 1.
There are several names: on of which is Proust's law.
Joseph Proust.
The law of constant proportion states that a pure chemical compound always contains exactly the same proportion of elements by mass.This information, together with the atomic masses of the elements in the compound enable scientists to determine the formula of a compound.
Weber's Law"Ernst Weber noted that for people to really perceive a difference, the stimuli must differ by a constant "proportion" not a constant "amount."
The law of constant proportions, also called Proust's law, states that the elements in a compound are all present in a fixed proportion by weight, regardless of how the compound is prepared.
There are several names: on of which is Proust's law.
Joseph Proust.
This was an idea of John Dalton.
The law of constant proportion states that a pure chemical compound always contains exactly the same proportion of elements by mass.This information, together with the atomic masses of the elements in the compound enable scientists to determine the formula of a compound.
percentage of mg
Weber's Law"Ernst Weber noted that for people to really perceive a difference, the stimuli must differ by a constant "proportion" not a constant "amount."
Joseph Louis Proust (1754-1826), In 1799 Proust stated that "Compounds always contain the same elements in a constant proportion by mass." This statement is now called law of definite composition or the law of constant proportion.
The law of constant proportions, also called Proust's law, states that the elements in a compound are all present in a fixed proportion by weight, regardless of how the compound is prepared.
Weber's Law
difference threshold
Dalton's law of constant proportion states that any sample of a chemical compound will have its constituent elements appearing in the same proportion by mass. Thus 8/9 of the mass of any sample of water will be oxygen and the remaining 1/9 will be hydrogen.
It means that in any pure compound, the proportion of constituent elements (by mass) is a constant. This allows their chemical formulae to be determined.