Chapter 2, Problem 1RQ

Use Dalton’s atomic theory to account for each of the following.

1. a. the law of conservation of mass
2. b. the law of definite proportion
3. c. the law of multiple proportions

Interpretation Introduction

Interpretation:

The law of conservation of mass, law of definite proportion and law of multiple proportions has to be explained on basis of Dalton’s atomic theory.

Concept Introduction:

Dalton’s atomic theory:

1. 1) Every element is composed of minute particles called as atoms.
2. 2) Atoms of same element are identical and atoms of different elements are non identical.
3. 3) When different atoms are combined together chemical compounds are obtained.
4. 4) Atoms themselves don’t take part in chemical reaction. Chemical reactions take place only by altering the way the atoms are bound together.

Answer to Problem 1RQ

Law of conservation of mass:

There is specific mass associated with atoms and these specified masses cannot be created or destroyed by chemical reactions.

Law of multiple proportions:

A series of compound is formed by combining two elements; the ratios of masses of second element that combines with one gram of the first element can be reduced to small whole numbers.

Law of definite proportions:

A compound always consist the same amount of elements (in proportion) by mass.

To explain: On basis of Dalton’s atomic theory, the law of conservation of mass, law of definite proportion and law of multiple proportions.

Explanation of Solution

Law of conservation of Mass

During a chemical reaction, the mass of atoms cannot be altered. The mass of atom always remains conserved in chemical reaction.  In other words, there is specific mass associated with atoms and these specified masses cannot be created or destroyed by chemical reactions.

Law of multiple proportions

The law of multiple proportions can be stated as a series of compound is formed by combining two elements; the ratios of masses of second element that combines with one gram of the first element can be reduced to small whole numbers.

Consider the following example,

Two different compounds can be formed from Carbon and Oxygen and the relative amounts of Carbon and Oxygen are also different.

Compound	Mass of Oxygen that combines with one gram of Carbon
Compound I	1.33 g
Compound II	2.66g

It can be seen that the compound II composes of twice the Oxygen per gram of Carbon. Compound II may be Carbon dioxide and Compound might be Carbon monoxide.  Thus, this principle is called as law of multiple proportions.

Law of definite proportions

The principle of constant composition of compounds can otherwise called as Proust’s law that can be stated as A compound always consist of the same amount of elements (in proportion) by mass.  In other words, the composition of substance depends on the number of kinds of atoms formed.  Certain compounds will always have the same number and types of atoms in their formula.

Conclusion

The law of conservation of mass, law of definite proportion and law of multiple proportions was explained.