Chapter 1 Atoms

Chemistry

The study of the composition, properties, and interactions of matter

It is also interconnected to a lot of other stem disciplines

_____ is a science based on observation

Chemists

____ study and describe how he behavior of matter and energy in 3 different domains

1) macroscopic domain

2) microscopic domain

3) symbolic domain

Hypothesis

A tentative explanation of observations.

Matter

Anything that occupies space and has mass

Theory

A well-substantiated, comprehensive, testable

explanation of a particular aspect of nature

Macroscopic domain

The realm of everyday things that are large enough to be sensed directly by human sight or touch

Microscopic domain

Almost always visited in the imagination. Micro also comes from Greek and means “small.” Some aspects of the microscopic domains are visible through a microscope

Symbolic domain

the specialized language used to represent components of the macroscopic and microscopic domains, such as chemical symbols

Plasma

A gaseous state of matter that contains an appreciable amount of electrically charged particles

Mass

A measure of the amount of matter in an object

Weight

Force that gravity exerts on an object

Law of conservation of matter

There is no detectable change in the total quantity of matter present when a phase change occurs

Element

Type of pure substance that cannot be broken down into simpler substances by chemical changes.

Compund

Pure substances that can be broken

down into simpler substances by chemical changes

Mixture

Composed of two or more types of

matter that can be present in varying amounts and

can be separated by physical changes

Homogeneous mixture

A uniform composition and appears visually the same throughout.

Heterogeneous mixture

A composition that varies from point to point

Just look at pic

Atom

The smallest particle of an element that has the properties of that element and can enter into a chemical combination

Physical properties

characteristic of matter that is not associated with a change in its chemical composition

Chemical property

The change of one type of matter into another type

(or the inability to change)

Extensive property

• Depends on the amount of matter present.

• Examples: mass, volume, heat

Intensive property

• Does not depend on the amount of matter present.

• Examples: density, temperature

• The size or magnitude of the measurement: a number

• A standard of comparison for the measurement: a unit

• An indication of the uncertainty of the measurement

Every measurement provides three kinds of

information:

Units

Without ____ a number can be meaningless or

confusing

Volume

The measure of the amount of space occupied by an object

Density

Mass divided by volume

Exact number

Result of counting measurements

Counting

The o my type of measurement free from uncertainty

Uncertain

Quantities derived from measurements other than counting are ____ to varying extents

Significant figures (sig fig)

All the digits in a measurement including the uncertain last digit

Precise

A measurement is said to be ____ if it yields very similar results when repeated in the same manner

Accurate

A measurement is considered ____ if it yields a result that is very close to the true or accepted value

2.54cm

1in