Laws

Definition

Laws in chemistry are fundamental principles that describe the consistent and predictable behavior of matter. They are derived from extensive experimental observations and validated through repeated testing.

5 Must Know Facts For Your Next Test

1. The Law of Conservation of Mass states that mass is neither created nor destroyed in a chemical reaction.
2. The Law of Definite Proportions asserts that a chemical compound always contains the same proportion of elements by mass.
3. The Law of Multiple Proportions notes that when two elements form more than one compound, the ratios of the masses of one element that combine with a fixed mass of the other element are ratios of small whole numbers.
4. Boyle's Law describes how the pressure of a gas tends to decrease as the volume increases, provided temperature remains constant: $P_1V_1 = P_2V_2$.
5. Charles's Law states that the volume of a gas is directly proportional to its temperature when pressure is held constant: $V_1/T_1 = V_2/T_2$.

Review Questions

• What does the Law of Conservation of Mass state about chemical reactions?
• How does Boyle's Law relate pressure and volume for gases?
• What principle does the Law of Definite Proportions emphasize about chemical compounds?

Related terms

Law: A statement based on repeated experimental observations describing some aspect of the world.

Theory: An explanation for observable phenomena which has been substantiated through extensive experimentation and evidence.

Hypothesis: A proposed explanation for an observation, which can be tested through experiments.