Exam #1

Question 1

Hypothesis

Answer 1

An unverified explanation of a natural phenonmenon

Question 2

Experiment

Answer 2

A procedure that tests the validity of a hypothesis

Question 3

Observation

Answer 3

Information determined by noting and a natural phenomenon

Question 4

Conclusion

Answer 4

An explanation of an observation that has been validated by repeated experiments that support a hypothesis.

Question 5

Pure Substance

Answer 5

A type of matter that has a definite composition.

Question 6

Element

Answer 6

A pure substance containing only one type of matter, which cannot be broken down by chemical methods.

Question 7

Homogenous Mixture

Answer 7

In a homogeneous mixture, also called a solution, the composition is uniform throughout the sample. We cannot see the individual components, which appear as one state. Familiar examples of homogeneous mixtures are air, which contains oxygen and nitrogen gases, and seawater, a solution of salt and water.

Question 8

Heterogenous Mixture

Answer 8

In a heterogeneous mixture, the components do not have a uniform composition throughout the sample. The components appear as two separate regions. For example, a mixture of oil and water is heterogeneous because the oil floats on the surface of the water. Other examples of heterogeneous mixtures are a cookie with raisins and orange juice with pulp.

Question 9

Solid

Answer 9

A state of matter that has its own shape and volume.

Question 10

Liquid

Answer 10

A state of matter that takes the shape of its container but has a definite volume.

Question 11

Gas

Answer 11

A state of matter that does not have a definite shape or volume

Question 12

Vaporization

Answer 12

The energy required to vaporize exactly 1 g of a substance at its boiling point. For water, 540 cal (2260 J) is needed to vaporize 1 g of liquid; 1 g of steam gives off 540 cal (2260 J) when it condenses at 100 °C.

Question 13

Condesation

Answer 13

The change of state from a gas to a liquid.

Question 14

Fusion

Answer 14

The energy required to melt exactly 1 g of a substance at its melting point. For water, 80. cal (334 J) is needed to melt 1 g of ice; 80. cal (334 J) is released when 1 g of water freezes at 0°C.

Question 15

Sublimation

Answer 15

The change of state in which a solid is transformed directly to a gas without forming a liquid first.

Question 16

Potential Energy

Answer 16

A type of energy related to position or composition of a substance.

Question 17

Kinetic Energy

Answer 17

The energy of moving particles.

Question 18

Calorie

Answer 18

Calories are referred to as either small (lowercase “c”) or large (uppercase “C”), with 1 large Calorie equalling 1,000 small calories. Scientifically,1 kcal or kilocalorie is equivalent to 1 large Calorie or 1,000 calories.

Question 19

calorie

Answer 19

The amount of heat energy that raises the temperature of exactly 1 g of water by exactly 1 °C.

Question 20

Joule

Answer 20

The SI unit of heat energy; 4.184 J = 1 cal.

Question 21

How is heat transferred?

Answer 21

Heat is transferred through three primary mechanisms: conduction (direct contact between molecules), convection (movement of heated fluid), and radiation (electromagnetic waves) - all occurring when there is a temperature difference between objects, with heat always moving from a hotter to a colder area.

Question 22

Specific Heat

Answer 22

A quantity of heat that changes the temperature of exactly 1 g of a substance by exactly 1 °C

Question 23

Scientific Method

Answer 23

The process of making observations, proposing a hypothesis, and testing the hypothesis; after repeated experiments validate the hypothesis, it may become a theory.

Question 24

Scientific Notation

Answer 24

A form of writing large and small numbers using a coefficient that is at least 1 but less than 10, followed by a power of 10.

Question 25

Chemical

Answer 25

A substance that has the same composition and properties wherever it is found.

Question 26

Chemistry

Answer 26

The study of the composition, structure, properties, and reactions of matter.

Question 27

Theory

Answer 27

An explanation for an observation supported by additional experiments that confirm the hypothesis.

Question 28

Submilation

Answer 28

The change of state in which a solid is transformed directly to a gas without forming a liquid first.

Question 29

Heat Curve

Answer 29

A diagram that illustrates the temperature changes and changes of state of a substance as it is heated.

Question 30

Heat

Answer 30

A state of matter that does not have a definite shape or volume.

Question 31

Compound

Answer 31

A pure substance consisting of two or more elements, with a definite composition, that can be broken down into simpler substances only by chemical methods.

Question 32

Mixture

Answer 32

The physical combination of two or more substances that are not chemically combined.