Theories, Laws, and other Concepts

Question 1

What are the five Postulates of Dalton’s Atomic Theory?

Answer 1

1. ) Matter is composed of exceedingly small particles called atoms. An atom is the smallest unit of an element that can participate in a chemical change.
2. )An element consists of only one type of atom, which has a mass that is characteristic of the element and is the same for all atoms of that element (Figure 2.2). A macroscopic sample of an element contains an incredibly large number of atoms, all of which have identical chemical properties.
3. )Atoms of one element differ in properties from atoms of all other elements.
4. )A compound consists of atoms of two or more elements combined in a small, whole-number ratio. In a given compound, the numbers of atoms of each of its elements are always present in the same ratio.
5. )Atoms are neither created nor destroyed during a chemical change, but are instead rearranged to yield substances that are different from those present before the change.

Question 2

This statement is known as the law of definite proportions or the law of constant composition.

Answer 2

all samples of a pure compound contain the same elements in the same proportion by mass.

Question 3

The law of multiple proportions states that….

Answer 3

when two elements react to form more than one compound, a fixed mass of one element will react with masses of the other element in a ratio of small, whole numbers.