Chapter 3, Problem 13A

Interpretation Introduction

Interpretation: The law of constant composition and how Dalton’s theory explains this law needs to be explained.

Concept introduction: Dalton’s atomic theory was proposed by John Dalton. Dalton’s model explained important observations. For example: the law of constant composition.

Answer to Problem 13A

Dalton's atomic theory explains law of constant composition.

Explanation of Solution

John Dalton, British teacher and scientist, explained concepts behind most natural materials are mixtures of pure substance, pure substances are either elements or combinations of elements called compound. Summarized explanation of these concepts is termed as Dalton’s atomic theory. Main ideas of Dalton’s atomic theory are mentioned below:

• This theory states that all matter is made of indestructible and indivisible atoms.
• All atoms of element have identified mass and properties.
• Each element has different atoms.
• Atoms can engage in a chemical reaction.
• Compound contain a definite and small number of atoms.

According to the Dalton’s atomic theory, matter is composed of tiny particles, all atoms of certain element are identical, compound contains more than one element. In law of constant composition, every sample of a compound has the same propositions of constituent elements.

Conclusion

Dalton’s atomic theory is based on the law of constant composition, law of multiple proportions, and the law of conservation of mass.