Chemistry Chapter 1

Atoms

submicroscopic particles that are the building blocks of matter

Molecules

atoms that are held together in a specific shape

what can affect the properties of substances

changes in structure and composition

Hypothesis

a tentative explanation of observations

Law

how nature behaves

Theory

model for the way nature behaves

Matter

anything that occupies space and has mass

State of Matter

solid, liquid, and gas

Composition

element, compound, mixtures

Solid

volume and shape independent of container, rigid, incompressible

Liquid

volume independent of container, no fixed shape, incompressible

Gas

no fixed volume or shape, conforms to container, compressible

Pure Substance

made up of only one component, and its composition dose not vary from one sample to another

Element

a pure substance that can't be broken down into simpler substances

Compound

a pure substance composed of two or more elements in a fixed definite proportion.

Mixture

composed of two or more components that can vary from one sample to another.

Heterogenous mixture

the mixture isn’t evenly mixed everywhere, so there variable composition one region of the mixture to another.

Homogenous mixture

the same composition throughout because its atoms or molecules are evenly mixed

Distillation

a way to separate substances in a mixture based on their boiling points

Filtration

a method used to separate a solid from a liquid using a filter

Physical changes alter what

the state or appearance (not the composition) of matter

Chemical changes alter what

the composition of matter. Atoms rearrange and transform the original substance into a different substance.

Physical properties

properties that a substance displaces without changing its composition. Examples include color, density, mass, odor, melting point, boiling point, and hardness.

Chemical properties

properties that substance displaces only changing its composition via a chemical change. Examples include flammability and reactivity with acid.

Intensive property

a characteristic that is independent of the amount of substance. Examples include melting point, temperature, odor, color, etc.

Extensive property

a characteristic that is dependent on the amount of substance. Examples include mass, volume, energy, etc.