Ch 1: Chemistry: The Central Science

Question 1

Accuracy is defined as….

Answer 1

…how close a measured value is to a true value.

Question 2

Precision is defined as….

Answer 2

….how close multiple measured values of the same are to one another.

Question 3

Define substance.

Answer 3

A form of matter that has a specific composition and distinct properties.

p. 6

Question 4

Substances can then be further classified as either ELEMENTS or COMPOUNDS. Define each of them.

Answer 4

An element is a substance that cannot be separated into simpler substances by chemical means.

A compound is a substance composed of atoms of two or more elements chemically united in fixed proportions.

Question 5

The elements that make up a compound are called the compound’s __________ ________.

Answer 5

constituent elements

p. 7

Question 6

A mixture is a combination of two or more substances, in which the substances retain their ________ identities. Unlike compounds, mixtures do not have a universal ________ composition. Therefore, samples of air collected in different locations will differ in composition because of differences in altitude, pollution, and other factors. The ratio of salt to water in different samples of salt water will vary depending on how they were prepared.

Answer 6

distinct
constant

p. 8

Question 7

In a homogeneous mixture, the mixture has a _______ _________ throughout, whereas in a heterogeneous mixture, the two substances remain distinct and ___________ from each other.

Answer 7

uniform composition

discernible

p. 8

Question 8

Mixtures, whether homogeneous or heterogeneous, can be separated into pure components by ________ means – without changing the identities of the components. After separation, the components of the mixture will have the same composition and properties as they did prior to being combined.

Answer 8

physical

p. 8

Question 9

The measured value of an extensive property of matter depends on the…

An example of an extensive property is ____.

Answer 9

….amount of matter.

mass

p. 15

Question 10

The value of an intensive property does NOT depend on the amount of matter. Two examples of intensive properties are…

Answer 10

…density and temperature.

p. 16

Question 11

Highly accurate measurements are usually precise, as well, although highly precise measurements do not necessarily guarantee ________ _______.

Answer 11

accurate results

p. 21

Question 12

SI Units, Prefixes:

tera (T)

Answer 12

10¹²

Question 13

SI Units, Prefixes:

giga (G)

Answer 13

10⁹

Question 14

SI Units, Prefixes:

mega (M)

Answer 14

10⁶

Question 15

SI Units, Prefixes:

kilo (k)

Answer 15

10³

Question 16

SI Units, Prefixes:

deci (d)

Answer 16

10^-1

Question 17

SI Units, Prefixes:

centi (c)

Answer 17

10^-2

Question 18

SI Units, Prefixes:

milli (m)

Answer 18

10^-3

Question 19

SI Units, Prefixes:

micro (μ)

Answer 19

10^-6

Question 20

SI Units, Prefixes:

nano (n)

Answer 20

10^-9

Question 21

SI Units, Prefixes:

pico (p)

Answer 21

10^-12

Question 22

A compound cannot be separated into simpler substances by any physical process. Instead, the separation of a compound into its constituent elements requires a _______ ________.

Answer 22

chemical reaction