Gen Chem ~ Chapter 1 Concepts

What is chemistry the study of?

The study of the composition and structure of materials and of the changes that materials undergo.

What are the 2 classifications of matter?

1. Substances

2. Mixtures

What is a substance?

Can’t be separated by physical means

What is a mixture?

Can be separated by physical means

What are the 2 types of mixtures?

1. Homogenous mixture

2. Heterogenous mixture

What is a homogenous mixture?

Can’t see the components, same throughout.

What is a heterogenous mixture?

Can see components, not same throughout.

What are some examples of a heterogenous mixture? (3)

Oil + water

Chocolate chip cookies

Granola bar

What are the 2 types of substances?

1. Elements

2. Compounds

What is an element? Can they be broken down?

Elements of the periodic table

Can’t be broken down into smaller particles

What is a compound?

Made up of 2 or more different types of atoms / elements.

What are the 7 diatomic elements?

1. H₂

2. O₂

3. N₂

4. F₂

5. Br₂

6. Cl₂

7. I₂

What are physical properties?

A characteristic that can be observed for a material without changing its chemical identity.

What are chemical properties?

A characteristic of a material involving its chemical change.

What are physical changes?

A change in the form of matter but not in its chemical identity.

What are chemical changes?

A change in which one or more kinds of matter are transformed into a new kind of matter or several new kinds of matter.

What are extensive properties?

A material depends upon how much matter is being considered

Examples of extensive properties? (3)

1. Mass

2. Length

3. Volume

What are intensive properties?

A material does not depend upon how much matter is being considered.

Examples of intensive properties? (3)

1. Density

2. Temperature

3. Color

What are measurements?

The comparison of a physical quantity to be measured with a unit of measurement

All measurements consist of what two parts?

1. Number

2. Unit

What are qualitative observations?

Descriptive in nature

Examples of qualitative observations? (2)

1. Changes in color

2. Changes in physical state

What are quantitative observations? (2)

Measurements

Counted values

What are exact numbers?

A number whose value has no uncertainty associated with it.

Exact numbers are found where? (3)

1. Definitions

2. Counting

3. Simple fractions

What are inexact numbers?

A number whose value has a degree of uncertainty associated with it.

Inexact numbers are the result of what?

Result of a measurement being taken

A digit that is estimated is what?

Uncertain.

What is accuracy?

How close a measurement is to the true value

What is precision?

How close a set of measurements are to each other