Chapter 1: Chemistry: The Central Science Sections 1-4

The study of materials and the changes that materials undergo:

chemistry

Anything that has mass and volume:

matter

Any characteristic that allows you to recognize a particular type of matter and to distinguish it from other types:

Property

The most basic substances found on the Periodic Table:

elements

The small building blocks of all matter:

atoms

Two or more atoms chemically combined:

molecules

Any elements and compounds are considered:

pure substances

Any substance composed of only one type of atom is an:

element

Two or more substances that are not chemically combined are:

mixtures

Two or more substances that are uniformly combined, like Kool-aid is called:

homogeneous mixture (also called solutions)

Two or more substances that are not uniformly combined, like a chocolate chip cookie is called:

heterogeneous mixture

This property of a substance can be observed without changing what the substance is, like color, state, melting point, density, solubility, etc.

physical property

This property of a substance can only be changed in the chemical makeup of a substance, like reactivity, combustibility, etc.

chemical property

The change in the property of a substance that is not chemically different from the original is called:

physical change

The change in the property of a substance that results in a chemically changed substance, like burning things is called:

chemical change

How do you know that a chemical change has occurred?

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Properties such as temperature, melting point, and density that do not depend on the amount of substance, is called:

intensive properties

Properties like mass and volume that depend on the amount of a substance is called:

extensive properties

The three states of matter are:

a gas, a liquid, or a solid

Pure Substance

is matter that has distinct properties and a composition that does not vary from sample to sample. (sodium chloride)

Number of elements known, though they vary widely in abundance?

118

Law of constant composition

elemental composition of a compound is always the same

Physical properites

can be observed without changing the identity and composition of the substance. (can include: color, odor, density, melting point, boiling point, and hardness)

Chemical properties

describe the way a substance may change , or react, to form other substances. (example: flammability. the ability of a substance to burn in the presence of oxygen)

Intensive properties

Properties, such as temperature and melting point

Extensive properties

depend on the amount of the sample, with two examples being mass and volume

An example of a physical change

Evaporation: water turning into vapor. Changing its physical change, but not its composition.

An example of a chemical change

When a substance is transformed into a chemically different substance. Hydrogen burns in air, combining with oxygen to form water.