TERM 4 CHEM STUDY GUIDE

stoichiometry

the process of calculating amounts of reactants and products in a reaction using the mole ratio from a balanced equation

mole ratio

a ratio that relates moles of one substance in the reaction to moles of another, as indicated in the balanced equation

limiting reactant

the reactant that runs out and causes the reaction to stop

mole

the amount of matter that contains avogadro's number of particles

avogadros number

6.02x10^23

molar volume

the space occupied by one mole of any gas at STP

molar mass

the mass of one mole of a substance

percent composition

the percentage by mass of each element in a compound

john dalton

he discovered that all matter is made of atoms, atoms are indivisible and indestructible, atoms of a given element are identical in mass and properties, and are different from atoms of other elements. He made the solid sphere model of an atom.

dalton's atomic theory

was the first complete attempt to describe all matter in terms of atoms and their properties

JJ thompson

He identifies a negatively charged entity within atoms, discovering the first subatomic particle. His experiment was the cathode ray tube, these deflected negative charges within the atom. He also called this the plum pudding model.

Ernest Rutherford

He discovers the positive charge in an atom is confined to a very small area. His experiment was the gold foil experiment. He also made the nuclear model.

Niels Bohr

He used mathematical models to explain light emission patterns, Bohr proposed that electrons exist at specific energy levels. His experiement was data from light emission spectra and mathematic calculations. His model was the planetary model.

evenly shared electrons

non polar covalent bonds

unevenly shared electrons

polar covalent bonds

ionic bonding

metal + non metal, electrons are transferred, mp and bp are very high, usually dissolves in water, and only will conduct electricity if molten or dissolved in water.

polar covalent bonding

non metal + non metal, electrons are shared unevenly, low mp/bp, usually dissolves in water, does not conduct electricity.

non polar covalent bonding

non metal + non metal, electrons are shared evenly, lowest mp and bp, usually does not dissolve in water, does not conduct electricity.

metallic bonding

metal + metal, sea of delocalized electrons, intermediate bp and mp, does not dissolve in water, and does conduct electricity.

law of conservation of mass

matter cannot be created nor destroyed by chemical or physical process.

coefficients

balance atoms in an equation

synthesis

multiple reactants becoming one thing

decomposition

one reactant becomes multiple products

combustion

a substance burns in oxygen, then yields to carbon dioxide and water

double replacement/ displacement

two ionic (nm+m) switch ions

neutralization

acid + base

single replacement/ displacement

one element displaces the similar element in the compound, or a metal displaces H from an acid.

dimitri mendeleev

designed a periodic table based on atomic mass- now it is based on atomic number

aufbau principle

electrons fill subshells and orbitals so the total energy of atom is the minimum

hund's rule

when filling a subshell/ sublevel, place electrons in unoccupied orbitals, in the same direction, before pairing them up.

pauli exculsion principle

up to two electrons may occupy the same orbital but must then have different spins

isotopes

atoms of the same element with a different number of neutrons/ different mass numbers

isomer

a structure with the same formula but different structure

chemistry

the study of matter and the changes that it undergoes

what is an element identified by?

the number of protons

what does the nucleus of an atom include?

protons and nuetrons

chemical reactions

rearrange atoms to produce chemicals different from those that were originally present

subscripts

the charge of an ion

mass number

the number of protons and neutrons in an atom

atomic mass

the weighted average of all of an elements isotopes

2

how many electrons fit in one orbital

no

do ionic bonds share electrons?

yes

do covalent bonds share electrons?

creates different ions

when you change the number of electrons on an atom