Chapter 1 - Chemical Foundations

Question 1

scientific method

Answer 1

the process of studying natural phenomena, involving observations, forming laws and theories, and testing of theories by experimentation.

Question 2

measurement

Answer 2

a quantitative observation.

Question 3

hypothesis

Answer 3

one or more assumptions put forth to explain the observed behavior of nature.

Question 4

theory

Answer 4

a set of assumptions put forth to explain some aspect of the observed behavior of matter.

Question 5

model

Answer 5

a set of assumptions put forth to explain the observed behavior of matter. The models of chemistry usually involve assumptions about the behavior of individual atoms or molecules.

Question 6

natural law

Answer 6

a statement that expresses generally observed behavior.

Question 7

SI unites

Answer 7

International System of units based on the metric system and units derived from the metric system.

Question 8

mass

Answer 8

the quantity of matter in an object.

Question 9

weight

Answer 9

the force exerted on an object by gravity.

Question 10

uncertainty

Answer 10

the characteristic that any measurement involves estimates and cannot be exactly reproduced.

Question 11

significant figures

Answer 11

the certain digits and the first uncertain digit of a measurement.

Question 12

accuracy

Answer 12

the agreement of a particular value with the true value.

Question 13

precision

Answer 13

the degree of agreement among several measurements of the same quantity; the reproducibility of a measurement.

Question 14

random error

Answer 14

an error that has an equal probability of being high or low.

Question 15

systematic error

Answer 15

an error that always occurs in the same direction.

Question 16

exponential notation

Answer 16

expresses a number as Nx10^m, a convenient method for representing a very large or very small number and for easily indicating the number of significant figures.

Question 17

dimensional analysis

Answer 17

an equivalence statement between units used for converting from one unit to another.

Question 18

density

Answer 18

a property of matter representing the mass per unit volume.

Question 19

matter

Answer 19

the material of the universe

Question 20

state of matter

Answer 20

the three different forms in which matter can exist; solid, liquid, and gas.

Question 21

physical changes

Answer 21

a change in the form of a substance, but not in its chemical composition; chemical bonds are not broken in a physical change.

Question 22

pure substance

Answer 22

a substance with constant composition.

Question 23

compound

Answer 23

a substance with constant composition that can be broken down into elements by chemical processes.

Question 24

chemical change

Answer 24

the change of substances into other substances through a reorganization of the atoms; a chemical reaction.

Question 25

elements

Answer 25

a substance that cannot be decomposed into simpler substances by chemical or physical means.

Question 26

homogeneous mixtures

Answer 26

a mixture having visibly indistinguishable parts.

Question 27

heterogenous mixtures

Answer 27

a mixture having visibly distinguishable parts.

Question 28

solution

Answer 28

a homogenous mixture

Question 29

filtration

Answer 29

a method for separating the components of a mixture containing a solid and a liquid.

Question 30

distillation

Answer 30

a method for separating the components of a liquid mixture that depends on differences in the ease of vaporization of the components.

Question 31

chromatography

Answer 31

the general name for a series of methods for separating mixtures by using a system with a mobile phase and a stationary phase.

Question 32

paper chromatography

Answer 32

the general name for a series of methods for separating mixtures by using a system with a mobile phase and a stationary phase.