Chapter 15.1 Classifying Matter. A. What is matter? 1. Matter is anything that has mass and takes up...

Chapter 15.1 Classifying Matter

A. What is matter?

• 1. Matter is anything that has mass and takes up space.

A. What is matter?

• 2. Matter can be classified into four different categories:

• a. Element

• b. Compound

• c. Homogeneous mixture

• d. Heterogeneous mixture

B. Pure Substances

• a. Matter with a fixed composition.

• b. Definite properties

• c. Each piece looks the same and has the same composition.

B. Pure Substances

• d. Classified as either an element or a compound.

• e. Cannot be separated by physical means.

• f. Examples: helium, aluminum, water, and salt

B. Pure Substances

• 1. Element

• a. All built from atoms.

• b. If all the atoms in a substance have the same identity, that substance is an element.

• c. Cannot be broken down into simpler substances by chemical means.

B. Pure Substances

• d. About 90 elements are found on Earth.

• e. More than 20 have been created in laboratories.

B. Pure Substances

• 2. Element Symbols

• a. Each element has a one or two letter symbol that is uses globally.

• b. First letter is always capitalized; if there is a second letter is it lowercase.

• c. Example: Symbol for carbon is C and the symbol for aluminum is Al.

B. Pure Substances•3. Compound

• a. A compound is a substance made up of atoms of different elements.

• b. Each molecule of a compound contains two or more elements that are chemically combined.

• c. Elements are found in a fixed proportion.

B. Pure Substances

•d. Compounds typically look different from the elements that make them up.

• i. Table salt is made of chlorine and sodium.

• ii. Chlorine is a toxic yellow-green gas and sodium is a highly-reactive silvery metal.

B. Pure Substances

• e. A chemical formula shows how many atoms of each element are in a unit of a substance.

• f. Examples: CO2, H2O, CO

C. Mixtures

• a. A combination of substances that are not chemically combined.

•b. Can be separated by physical means.

• c. Categorized by how well their substances are mixed.

•d. Two categories of mixtures: homogeneous and heterogeneous.

C. Mixtures• 1. Heterogeneous Mixtures

• a. Substances are not evenly distributed.

• b. No pattern

• c. Examples include granite, oil and vinegar, and a shirt (cotton and polyester are not evenly distributed.

C. Mixtures•2. Homogeneous Mixtures

• a. Components are evenly distributed and the mixture is the same throughout.

• b. Distinct pattern

• c. Examples: salt water and iced tea

Type of Matter Substance Mixture

1. Chlorine

2. Water

3. Soil

4. Sugar water

5. Oxygen

6. Carbon dioxide

7. Rocky road ice cream

8. Alcohol

9. Pure air

10. Iron

D. Solutions, Colloids, and Suspensions

• 1. Solution

• a. Homogeneous mixture

• b. Particles will never settle to the bottom of their container

• c. Always uniformly mixed

• d. Example: salt water

D. Solutions, Colloids, and Suspensions

• 2. Colloid

• a. Particles larger than a solution, but not heavy enough to settle out.

• b. Colloids scatter light.

• i. Scattering of light by colloidal particles is called the Tyndall effect.

• ii. Can distinguish a solution from a colloid.

• c. Examples: milk, paint, fog, and milk.

D. Solutions, Colloids, and Suspensions

• 3. Suspension

• a. Heterogeneous mixture

• b. Contains a liquid in which visible particles settle out.

• C. Example: muddy water

Comparing Solutions, Colloids, and Suspensions

Description Solutions Colloids Suspensions

Settle upon standing?

No No Yes

Separate using Filter Paper?

No No Yes

Particle size 0.1-1 nm 1-100 nm > 100 nm

Scatter light? No Yes yes