Chem Midterms Review

Pauli Exclusion Principle

no two electrons in an atom can have the same four quantum numbers.

Aufbau Principle

electrons occupy the lowest-energy orbitals first

Hund’s Rule

In orbitals of equal energy (degenerate orbitals), electrons fill singly first with parallel spins, then pair up

atomic number/protons + neutron number

formula for mass number

Linear (180 deg)

2 electron groups

Trigonal Planar (120 deg)

3 groups

Tetrahedral 109.5 deg

4 groups

Trigonal Bipyramidal (90 deg, 120 deg)

5 groups

Octahedral (90 deg)

6 groups

paramagnetic atom

lone pair/ unpaired

diamagnetic atom

paired

polar bond

electronegativity difference greater than 0.5

limiting reagents

the reactant that runs out first

excess reagent

left over reagent

intermolecular forces

the force holding the particles together

kinetic energy

the energy an object possesses due to its motion of the particles

Boyle’s law

Pressure Volume relationship at constant Temperature, the gas volume decreases as pressure increases.

Charle’s Law

Volume and Temperature relationship at constant Pressure; the gas volume increases as the temperature increases

Gay Lussac’s Law

Pressure and Temperature relationship at constant n (no of moles) and Volume; as the temperature decreases, particles slow down

open system

there is mass transfer and heat transfer

closed system

there is no mass transfer but there is heat transfer

isolated system

no mass transfer and no heat transfer

entropy

heat flows from hot to cold

endothermic

q > 0

exothermic

q <0

(+) or positive

w > 0 ; work done on system

(-) or negative

w < 0 ; work is done by the system

heat capacity

the amount of energy required to raise the temperature of a substance by 1 deg C