Chemistry Final

lab safety equipment

safety shower
eye wash station
safety goggles
fire extinguisher
fire blanket
fume hood
gloves
lab coat

lab safety guidelines

read entire lab before starting
all chemicals should be treated as if they are dangerous

chemistry

the study of matter and how it changes

pure research

gaining knowledge for the sake of knowledge

applied research

gaining knowledge to solve a specific problem

mass

measurement of an amount of matter

weight

measurement of an amount of matter and its gravitational pull

model

visual, verbal, or mathematical explanation of data

SI base units

time - seconds
length - meter
mass - kilogram
temperature - Kelvin
amount of a substance - mole

Derived units

combination of base units

accuracy

how close a measurement is to the true value

precision

how detailed a measurement is

error

measure of accuracy

significant figures

measure of precision

sig fig rules

Non-zero digits are always significant.
Any zeros between two significant digits are significant
ONLY a final zero or trailing zeros in the decimal portion are significant.

Example: .500 or .632000 the zeros are significant. 006 or .000968 the zeros are NOT significant

circle graph

best for showing multiple parts that make up one whole amount

bar graph

best for comparing amounts of different things

line graph

best for showing how a single thing changes

interpolation

estimates from within data range shown

extrapolation

estimates from outside data

substance

matter with a uniform and unchanging composition

solids

definite shape and volume

liquids

flow, constant volume, take shape of container

gases

flow, take shape and volume of container

vapor

gaseous form of a liquid/solid

physical properties

a characteristic of matter that can be observed or measured without changing substance composition

extensive properties

depend on amount (mass, volume, length, shape)

intensive poperties

do not depend on amount (color, texture, smell, taste, hardness, density, melting and boiling point)

chemical properties

ability or inability of a substance to combine or change into another substance

physical change

change in physical properties but not composition

phase change

transition between states of matter

chemical change

changes from one substance to another

Law of Conservation of Mass

matter is never created or destroyed in a chemical reaction (mass of reactants = mass of products)

element

pure substance that cannot be separated into simpler substances

periodic table

a way to organize the elements by shared properties

compound

elements combined chemically

mixtures

combination of two or more substances in which each substance retains its chemical properties

heterogenous mixtures

a mixture that does not blend smoothly and in which the individual substances remain distinct and are more easily separated (fruit salad, italian dressing)

homogenous mixtures

a mixture that is blended smoothly (has a single phase), has a constant composition, are more difficult to separate (Koolaid, brass)

solution

A homogeneous mixture of two or more substances

filtration

typically used on heterogenous mixtures

distillation

typically used on homogenous mixtures

sublimation

a solid turns into a gas without becoming a liquid

chromatography

separates ingredients in a liquid

crystallization

results in the formation of pure solid particles of a substance from a solution containing the dissolved substance

percent by mass formula

mass of element/mass of compound x 100

Democritus

Greek philosopher that said all matter is made of tiny particles called "atomos" or atoms

Aristotle

Four elements make up the world; earth, air, fire, water

John Dalton

English chemist and physicist who formulated atomic theory

atomic theory

theory that states all matter is composed of tiny particles called atoms

atom

Smallest particle of an element

cathode ray tube experiment

experiment that led to the discovery of the electron and the development of the plum pudding model of the atom

plum pudding model

model of an atom that shows randomly distributed electrons within a positively charged cloud

nuclear model

model of an atom with protons and neutrons in the nucleus and electrons outside the nucleus

gold foil experiment

alpha particles were shot at gold foil and deflected when they hit the positive center of gold atoms, causing the discovery of the nucleus

electron

negatively charged particle in the space around an atom's nucleus

proton

positively charged particle in an atom's nucleus

neutron

particle with no charge in an atom's nucleus

nucleus

center of an atom

chemical name

name of an element on the periodic table

chemical symbol

A one or two letter representation of an element

atomic number

number of protons in nucleus (number of electrons is the same)

atomic mass

weighted average of masses of all isotopes of an element

isotopes

atoms of an element (same number of protons) with different number of neutrons

mass number

atomic number + number of neutrons

atomic mass units (amu)

1 proton/neutron

radioactivity

spontaneous radiation of energy and/or particles

radiation

rays and particles emitted by radioactive material

nuclear radiation

a reaction that changes an atom's nucleus

radioactive decay

unstable nuclei losing energy through spontaneous radiation

alpha radiation

positively charged (2+)
largest radiation (alpha particle)
least energetic
can be blocked by skin, paper

beta radiation

negatively charged (1-)
low mass (beta particle)
medium energy
can be blocked by a thin layer of aluminum

gamma radiation

no charge
no mass (gamma ray)
very high energy
can be reduced in intensity by very dense substances (such as lead)

electromagnetic radiation

a form of energy that exhibits wavelike behavior as it travels through space (visible light)

quantum

minimum amount of energy that can be gained or lost by an atom

photon

massless particle that carries a quantum of energy

photoelectric effect

The emission of electrons from a metal when light shines on the metal

atomic emission spectrum

light energy given off by an energized element, unique to the element

ground state

lowest allowable energy state of an atom

excited state

when an atom gains energy

quantum number

number representing the energy level of an orbital

quantum mechanical model

the modern description of the electrons in atoms

Heisenberg uncertainty principle

it is impossible to know exactly both the velocity and the position of a particle at the same time

atomic orbital

describes the electron's probable location

energy sublevels

increasing number of orbitals and orbital shapes in an energy level (s, p, d, f)

electron configuration

the arrangement of electrons in an atom

valence electrons

electrons in an atom's outermost orbitals

periodic table

chart that organizes all known elements into a grid of horizontal rows and vertical columns arranged by increasing atomic number

periodic law

elements are arranged by increasing atomic number

period

horizontal row of elements in the periodic table

group

vertical column of elements in the periodic table

representative elements

elements in groups 1, 2, and 13 to 18

transition elements

elements in groups 3 to 12

metal

- generally shiny
- solids at room temp (except Hg)
- good conductors of heat/electricity
- malleable and ductile

malleable

can be pounded into a thin sheet

ductile

can be pulled into a thin thread

alkali metals

group 1 metals, very reactive

alkaline earth metals

group 2 metals, very reactive

transition metals

located in groups 3-12

inner transition metals (lanthanide/actinide series)

located along the bottom of the periodic table