I. Density
Matter has Mass & Volume
1. Matter- Anything that has mass and takes up space
2. The space an object occupies is its volume
1. Volume—a measure of the size of a body or region in three-dimensional space
2. The method used to determine volume depends on the nature of the matter being examined
3. #### Quantity of Matter is Mass

1. Mass- a measure of the amount of matter in an object. It is not affected by the gravitational force
2. Balances measure mass usually in grams
3. It is the same no matter where it is in the universe
4. #### Mass is NOT Weight

1. Weight- the force produced by gravity action on mass
2. Its value can change with the location of the object in the universe
3. Measured in Newtons

### II. Units of Measurement

1. Mass & volume are properties that can be described in terms of numbers
1. Numbers alone aren’t enough because their meaning might be unclear
2. Units of measurement are needed with the numbers
Quantity- something that has magnitude, size, or amount
Unit- a quantity adopted as a standard of measurement
1. System Internationale d’Units
1. Seven base units
2. Base units can be modified by attaching prefixes
2. #### Derived Units

1. Many quantities you can measure need units other than the seven basic SI Units
2. These units are derived by multiplying or dividing the base units
1. ### Properties of Matter

Properties of substances may be classified as physical or chemical

#### Physical Properties

1. Characteristic of a substance that doesn’t involve a chemical change, such as density, color, or hardness
2. ### Chemical Properties

1. A property of matter that describes a substance’s ability to participate in chemical reactions
2. Examples: reactivity with oxygen, sensitivity to light, exposure to heat
3. ### Density

1. Density- the ratio of mass to volume of a substance. Often expressed in grams/cm3 for solids and liquids and g/L for gases
Density= mass/volume or D=m/v
1. ## Classifying Matter

-From the last section:
-Matter-anything that has mass and takes up space
-All matter is composed of Atoms
-Atom- the smallest unit of an element that maintains the properties of that element
Because matter exists in so many different forms, having a way to classify it is important for study.
It helps you to predict what characteristics a sample will have based on what you know about others like it.