Chapter 2 Classifying Matter (p



2.1.1 notes Name/Date: _________________________

Chapter 2 Classifying Matter (p. 38)

1. Elements-the atoms in a sample of matter are alike; can’t be broken down into simpler substances (i.e. Carbon or Hydrogen or Helium)

2. Substance-matter that is an element or a compound (i.e. Carbon or H20)

3. Compounds- substance that is made from 2 or more simpler substances (elements)

▪ The ratio of atoms is always the same, fixed proportion. (i.e. H20, CO2)

▪ Properties of the compound are different from the properties of the simpler substances that make them up

4. Mixture-material made up of two or more substances that can be separated by physical means (i.e. salt water)

▪ Proportions are not fixed; not in specific ratio

5. Homogeneous mixture-material in which 2 or more substances are uniformly spread out (all looks the SAME)

6. Heterogeneous mixture-mixture in which different materials can be easily distinguished (can see the different parts/pieces)

7. Solution-homogeneous mixture of two or more substances

▪ Particles are very small and remain mixed together; i.e. alcohol

▪ A substance that cannot be dissolved in a given solvent is called insoluble.

8. Suspension-heterogeneous mixture that separates into layer over time (settles)

9. Colloid-heterogeneous mixture that contains some particles that are intermediate in size between the small particles in a solution and the larger particles in a suspension

▪ Examples: milk, fog, smoke

▪ One way to tell a colloid from a solution is to use the Tyndall effect. The Tyndall effect scatters light because of the particles in the mixture.

Classes of elements

Metals:

□ Good conductors of heat and electricity

□ Malleable-they can be hammered or rolled into sheets

□ Ductile-they can be drawn into wires

Nonmetals:

• Most nonmetals are gases at room temperature

• Poor conductors of heat and electricity

Hydrogen is considered a non-metal

Metalloids: elements with properties that fall between metals and nonmetals

• Along the stair-step line on the periodic table

Sample questions:

1. What is one characteristic of metals?

a. They dissolve in water. b. They burn in air.

c. They conduct electricity. d. They are highly reactive.

2. If a substance contains only one kind of atom and cannot be broken down by chemical means, it is called what? A. An element b. a mixture c. a compound d. a molecule

3. Which of the following is a mixture?

a. Sugar b. water c. air d. salt

4. Which of the following is a homogeneous mixture?

a. Liquid b. solution c. substance d. suspension

5. Which of the following is a substance?

a. Lemonade b. soil c. seawater d. steam

6. What is a solution?

a. Type of element b. type of molecule

c. homogeneous mixture d. heterogeneous mixture

7. Which one of the following statements about compounds is true?

a. They are pure substances that form when two or more different atoms are combined.

b. They are mixtures that can be separated only by physical means

c. They always consist of identical atoms.

d. They always have the characteristics of the elements from which they were formed.

8. Which material would be classified as homogeneous?

a. stainless steel bolt b. granite rock c. soda pop d. apple

9. Which of the elements listed is a metalloid?

a. carbon b. antimony c. sulfur d. helium

10. What classification would best describe a material with the following characteristics?

-white liquid -not separated by filtration - scatters light

a. element b. solution c. colloid d. suspension

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