Can someone please explain to me what was John Dalton's experiment that led to his atomic theory? I know it's the electrolysis of water, but I'd appreciate if someone could explain in detail.
Sorry, electrolysis of water was what was stated in the book.
In short, by observing that particles making up gases were different, he was able to get the following:
- All atoms of the same element are identical in mass and size from the atoms of other elements.
- Compounds are formed when atoms of different elements combine in fixed proportions.
Well, John Dalton's experiment was actually quite electrifying! Instead of electrolysis of water, he focused on a different concept called the Law of Multiple Proportions. You see, Dalton observed that when elements combine to form compounds, they do so in fixed ratios by weight.
To explain this, Dalton used the analogy of a circus. Imagine you have a lion tamer and a clown in a team. The lion tamer always brings two lions, while the clown prefers to juggle three balls. Now, in a compound formed by these two circus performers, you would expect the ratio of lions to balls to be constant. Let's say we have a compound called "Lionclownite!" In every molecule of Lionclownite, you'd find two lion atoms and three ball atoms.
This was Dalton's "Big Top" discovery! He concluded that elements are made up of tiny, indivisible particles called atoms. And these atoms, like our circus performers, combine in fixed ratios to form compounds. This led to the development of Dalton's atomic theory, which revolutionized our understanding of matter.
So, while Dalton didn't specifically do an experiment with electrolysis of water, his observations of proportions in compounds laid the foundation for modern atomic theory.
Certainly! John Dalton's atomic theory was not directly established through an experiment involving the electrolysis of water. Instead, it was formulated based on various experimental observations and scientific data available during his time.
Here's a breakdown of the experiments and observations that played a significant role in Dalton's atomic theory:
1. Law of Conservation of Mass: Dalton considered the work of Antoine Lavoisier, who had previously discovered the Law of Conservation of Mass. This law states that in a chemical reaction, the total mass of the reactants is equal to the total mass of the products. Dalton recognized this as evidence for the existence of atoms, reasoning that since atoms are indivisible, they must be rearranging themselves during chemical reactions and conserving their mass.
2. Law of Definite Proportions: Dalton studied the works of Joseph Proust, who discovered the Law of Definite Proportions. This law states that a compound always contains the same elements in the same proportion by mass. Dalton interpreted this as evidence that compounds are formed by the combination of atoms in fixed ratios.
3. Law of Multiple Proportions: Dalton also considered the Law of Multiple Proportions, formulated by John Dalton's contemporary, Joseph Louis Gay-Lussac. This law states that when two elements combine to form multiple compounds, the mass ratios of one element to the other can be expressed as small whole numbers. This observation further supported the idea of atoms combining in fixed ratios.
4. Dalton's own experiments: Dalton performed various experiments related to gas behavior and the behavior of solutions. While these experiments were not specifically tied to the development of his atomic theory, they provided him with valuable data that he used in formulating his ideas.
It's important to note that Dalton's atomic theory was a theoretical framework he developed to explain the experimental observations of his time. The specific experiment you mentioned, the electrolysis of water, is not directly related to Dalton's atomic theory, but rather contributed to our understanding of the composition of water molecules later on.
In summary, John Dalton's atomic theory was developed based on the combination of existing experimental observations and scientific data available during his time, including the works of other scientists.
You know it is electrolysis of water? Really?
ohn Dalton (1766-1844) developed the first useful atomic theory of matter around 1803. In the course of his studies on meteorology, Dalton concluded that evaporated water exists in air as an independent gas. He wondered how water and air could occupy the same space at the same time, when obviously solid bodies can't. If the water and air were composed of discrete particles, Dalton reasoned, evaporation might be viewed as a mixing of water particles with air particles. He performed a series of experiments on mixtures of gases to determine what effect properties of the individual gases had on the properties of the mixture as a whole. While trying to explain the results of those experiments, Dalton developed the hypothesis that the sizes of the particles making up different gases must be different. He later wrote [1]
"...it became an object to determine the relative sizes and weights, together with the relative numbers of atoms entering into such combinations... Thus a train of investigation was laid for determining the number and weight of all chemical elementary particles which enter into any sort of combination one with another."
Dalton's exceptional gift for recognizing and interpreting patterns in experimental data lead him from a problem in meteorology to the idea of atoms as fundamental constituents of matter. He realized the vital theoretical connection between atomic weights and weight relations in chemical reactions. He was the first to associate the ancient idea of atoms with stoichiometry.