Ch1 Matter & Measurement

Question 1

Property

Answer 1

Any characteristic that allows us to recognize a particular type of matter and to distinguish it from other types.

Question 2

Element

Answer 2

A substance consisting of atoms of the same atomic number. A substance that cannot be separated into simpler substances by chemical means.

Question 3

Atom

Answer 3

The smallest representative particle of an element.

Question 4

Molecule

Answer 4

A chemical combination of two or more atoms.

Question 5

Gas

Answer 5

No fixed volume or shape; uniformly fills its container. Can be compressed to occupy smaller space or expand for larger.

Question 6

Liquid

Answer 6

Distinct volume independent of its container. Assumes shape of portion of container it occupies.

Question 7

Solid

Answer 7

Definite shape and volume.

Question 8

(Pure) Substance

Answer 8

Matter that has distinct properties and a composition that foes not vary from sample to sample.

Question 9

Compounds

Answer 9

Substances composed of two or more elements; they contain two or more kinds of atoms.

Question 10

Law of constant composition
Or
Law of definite proportions

Answer 10

Elemental composition of a compound is always the same.

Question 11

Solution

Answer 11

Homogeneous mixture

Question 12

Physical properties

Answer 12

Observed w/o changing the identity and composition of the substance.
Color, odor, density, melting point, boiling point, hardness.

Question 13

Chemical properties

Answer 13

The way the substance may change or react to form other substances.
Flammability.

Question 14

Intensive properties

Answer 14

Don’t depend on the amount of sample being examined and are particularly useful to identify substances.
Temperature and melting point

Question 15

Extensive properties

Answer 15

Depend on the amount of sample.

Mass and volume

Question 16

Physical change

Answer 16

Substance changes its physical appearance but not its composition.
W
Eg water evaporation

Question 17

Chemical change/reaction

Answer 17

Substance is transformed into a chemically different substance.
Eg hydrogen burns in air–combines w/ oxygen to form water.

Question 18

Distillation

Answer 18

Method of separating the components of a homogeneous mixture. A process that depends on the different abilities of substances to form gases.
Eg boil salt water– water evaporates and leaves salt behind.

Question 19

Theory

Answer 19

A predictive model that accounts for all observations.

Question 20

Scientific law

Answer 20

When nature behaves in a certain way over and over again, under all sorts of conditions.

Question 21

SI Base Units

Answer 21

Mass-kilogram-kg
Length-meter-m
Time-second-s or sec
Temperature-kelvin-K
Amount of substance-Mole-mol
Electric Current-ampere- A or amp
Luminous intensity-Candela-cd

Question 22

Matter

Answer 22

The physical material of the universe; has mass and occupies space.

Question 23

Temperature

Answer 23

Measure of hotness or coldness of an object, is a physical property that determines the direction of heat flow.

Question 24

Celsius scale

Answer 24

0 degrees C – freezing point of water.

100 degrees C – boiling point at sea level.

Question 25

Absolute zero

Answer 25

Zero on the kelvin scale– -237.15 degrees C

Question 26

Kelvin and Celsius relation

Answer 26

K = degreeC + 273.15

Freezing point of water 0 degree C is 273.15K

Question 27

Fahrenheit to Celsius Formula

Answer 27

C = 5/9 (F - 32)

Question 28

Celsius to Fahrenheit Formula

Answer 28

F = 9/5 (C) + 32

Question 29

Derived unit

Answer 29

Obtained by multiplication or division of one or more base units.

Question 30

Precision

Answer 30

Measure of how closely individual measurements agree with one another.

Question 31

Accuracy

Answer 31

How closely individuals measurements agree with the correct or “true” value.

Question 32

Significant figures in calculations:
Addition and subtraction
&
Multiplication and division

Answer 32

The result has the same number of decimal places a the measurement with the fewest decimal places.
&
The result contains the same # of significant figures as the measurement with te fewest significant figures.

Question 33

Dimensional analysis

Answer 33

Units are multiplied together or divided into each other along with the numerical values.

Question 34

Conversion factor

Answer 34

Fraction whose numerator and denominator are the same quantity expressed in different units.
Eg 2.54 cm = 1 in.
# of cm = (8.50 in.) 2.54 cm/1 xin.x = 22.6 cm