Lesson 2

Question 1

Matter whose composition does not change from one sample to another
is called a

Answer 1

Pure substances

Question 2

Pure substances
• made of a single type of atom or molecule
• Because the composition of a pure substance is always the same, all samples have the same characteristics

Question 3

• Matter whose composition may vary from one sample to another is call a

Answer 3

Mixture

Question 4

Mixture:
•two or more types of atoms or molecules combined in variable
proportions
• Because composition varies, different samples have different characteristics.

Question 5

Pure substances that cannot be
decomposed into simpler substances by chemical reactions are called

Answer 5

Elements

Question 6

Elements:
decomposed = broken down
•basic building blocks of matter
•composed of single type of atom
• though those atoms may or may not be combined into molecules

Question 7

Substances that can be decomposed are called

Answer 7

Compounds

Question 8

Compounds
•chemical combinations of elements
•composed of molecules that contain two or more different kinds of atoms
• All molecules of a compound are identical, so all samples of a compound behave the same way.
• Most natural pure substances are compounds.

Question 9

-mixture that has uniform composition throughout.

-Every piece of a sample has identical characteristics, though another sample with the same components may have different characteristics.

-atoms or molecules mixed uniformly

Answer 9

Homogenous

Question 10

mixture that does not have uniform composition throughout

contains regions within the sample with different characteristics atoms or molecules not mixed uniformly

Answer 10

Heterogenous

Question 11

Heterogenous
Example:
Oil and water, chocolate chip cookies,
Cereal in milk

Question 12

Homogenous
Example:
Air, wine, blood, coffee

Question 13

Examples of physical properties include:

•Color, Pressure
•Shape, Solubility
•Volume, Viscosity
•Density, Electric charge
•Temperature
•Boiling point

Question 14

Chemical properties:
Flammability
Reactivity
Toxicity

Question 15

Intensive properties do not depend on the amount of matter in a sample.

Answer 15

Intensive property

Question 16

Extensive properties depend on how much matter a sample contains

Answer 16

Extensive properties

Question 17

is a process to separate mixtures by removing a liquid layer that is free of a precipitate, or the solids deposited from a solution. The purpose may be to obtain a decant (liquid free from particulates) or to recover the precipitate.

Answer 17

Decantation

Question 18

is a process used to separate solids from liquids or gases using a filter medium that allows the fluid to pass through but not the solid. The term “filtration applies whether the filter is mechanical, biological, or physical. The fluid that passes through the filter is called the filtrate.

Answer 18

Filtration

Question 19

is the process of separating components of a mixture based on different boiling points

Answer 19

Distillation

Question 20

is used to separate a soluble solid from a liquid. For example, copper sulfate is soluble in water- its crystals dissolve in water to form copper sulfate solution. the water evaporates away leaving solid copper sulfate crystals behind.

Answer 20

Evaporation

Question 21

technique to separate solid particles dispersed in liquid medium, eg.. blood cells and plasma

Answer 21

Centrifugation

Question 22

is the process of separating components of mixtures by using magnets to attract magnetic materials

Answer 22

Magnetic separation

Question 23

is a method of separating mixtures by using a moving solvent on filter paper. A drop of mixture solution is spotted near one end of the paper and then dried. The end of the paper, nearest the spot, is then dipped into the solvent without submerging the spot itself.

Answer 23

Chromatography