Ch. 1

Question 1

Hypothesis

Answer 1

a tentative explanation/prediction in accord with current knowledge

Question 2

Law

Answer 2

a concise verbal or mathematical statement of a behavior/relation that seems always to be the same under the same conditions

Question 3

Theory

Answer 3

a well-tested, unifying principle that explains a body of facts and the laws based on them
capable of suggesting new hypotheses that can be tested experimentally
where someone has made a guess/an idea is not yet substantiated

Question 4

How are laws established?

Answer 4

once a theory has been tested thoroughly and is accepted
based on results from many experiments by many different scientists over time

Question 5

Solids

Answer 5

rigid shape and fixed volume
particles are packed closely together, vibrate back and forth
large net forces of attraction

Question 6

Liquids

Answer 6

fixed volume and takes on shape of container (fluid, no definite shape)
particles arranged randomly, not confined to specific locations
medium net force of attraction

Question 7

Gases

Answer 7

fluid and volume depends on size of container (varies more than liquid)
particles move rapidly, not constrained by neighbors and colliding with each other and container walls
small net force of attraction

Question 8

Solution

Answer 8

a homogeneous mixture of one or more solutes dissolved in solvent

Question 9

Pure substances

Answer 9

set of unique properties
fixed composition, cannot be further purified

Question 10

Mixtures

Answer 10

two or more pure substances that can be separated by physical techniques
composition can be varied

Question 11

Homogeneous mixtures

Answer 11

uniform composition throughout (two or more substances in the same phase)
often called solutions
Ex: air, gasoline, sugar water, steel

Question 12

Heterogeneous mixtures

Answer 12

nonuniform composition
uneven texture of material can often be detected by naked eye
properties in one region are different from those in another region
Ex: milk, oil and water, sandy water

Question 13

Atoms

Answer 13

smallest particle of an element that retains the characteristic chemical properties of that element

Question 14

Elements

Answer 14

cannot be subdivided by chemical or physical processes
substances composed of only one type of atom

Question 15

Molecule

Answer 15

particles consisting of more than one atom in which atoms are held together by chemical bonds

Question 16

Compound

Answer 16

elements united in fixed ratio
substance which is composed of two or more DIFFERENT elements held together by chemical bonds
properties different than those of constituent elements

Question 17

Law of definite proportions
(law of constant composition)

Answer 17

a compound has a definite composition (by mass) of its combining elements

Question 18

Physical properties of common substances

Answer 18

color
state of matter
melting point
boiling point
density
solubility
electric conductivity
malleability
ductility
viscosity

Question 19

Chemical changes

Answer 19

one or more substances (reactants) are transformed into one or more different substances (products)

Question 20

Physical changes

Answer 20

identity of substance is preserved even though it may have changed its physical state
does NOT result in new chemical substance being produced

Question 21

Chemical properties of common substances

Answer 21

Ex: Hydrogen gas reacts violently with oxygen gas

Question 22

Types of kinetic energy (energy associated with motion)

Answer 22

thermal: motion of atoms, molecules, or ions at submicroscopic level
mechanical: motion of macroscopic objects
electrical: movement of electrons in a conductor
acoustic: compression/expansion of the spaces between molecules in the transmission of sound

Question 23

Types of potential energy (results from an object’s position or state)

Answer 23

gravitational: energy possessed by ball held above floor and by water at top of water wheel
energy stored in an extended spring
chemical: energy stored in fuels
electrostatic: energy associated with the separation of electrical charges

Question 24

Law of conservation of energy

Answer 24

energy cannot be created or destroyed
total energy of the universe is constant