Unit 2 Part A Vocabulary

Chemical change: any change from one state (gas, liquid, solid) which is accompanied by alteration of the chemical composition; any process in which one or more substances are changed into one or more different substances

Conservation of mass: the principle that the total mass of any isolated system is constant and is independent of any chemical and physical changes taking place within the system

Physical change: a usually reversible change in the physical properties of a substance, as size or shape

Solution: the process by which a gas, liquid, or solid is dispersed homogeneously in a gas, liquid, or solid without chemical change

Unit 2 Part B Vocabulary

Hypothesis: a proposition, or set of propositions, set forth as an explanation for the occurrence of some specified group of phenomena

Law: a statement based on repeated experimental observations that describes some aspects of the universe

Theory: a supposition or a system of ideas intended to explain something, especially one based on general principles independent of the thing to be explained

Law of Conservation of Mass:

Mass is neither created nor destroyed.

What are the macroscopic and microscopic differences between physical and chemical changes?

Macroscopic Definitions:

Physical Change - The matter is the same. The original matter can be recovered.

Chemical Change - Matter is different. The old matter is no longer present. The original matter cannot be recovered.

Microscopic Definitions:

Physical Change - The particles of the substance are rearranged.

Chemical Change - The particles of the substance are broken apart, and the atoms are rearranged into new particles, forming a new substance.