TTU CHEM 1307 Exam 3

Hurd Rule

electrons singly occupy, with parallel spins, all the degenerate orbitals within a subshell before spin-pairing electrons in an orbital

Pauli Exclusion Principle

no two electrons can have the same four quantum numbers

subshells

number of orbitals

number of electrons

s (l=0), 1 orbital, 2 electrons

p (l=1), 3 orbitals, 6 electrons

d (l=2), 5 orbitals, 10 electrons

f (l=3), 7 orbitals, 14 electrons

periodic table reference orbitals

ionization energy

The amount of energy required to remove an electron from an atom

longer wavelength than 579 nm

lower energy and won't eject an electron

shorter wavelength than 579 nm

higher energy and will eject an electron

579 nm

the maximum of longest wavelength that can eject an electron

Enthalapy

The heat content of a system at constant pressure

H= E + PV

Constant pressure

Cp= △H

Calormetry

measurement of the amount of heat released or absorbed during a chemical reaction

Endothermic Reaction

rxn absorbs energy as heat making the surroundings colder because of lost heat

△Hrxn is positive

Exothermic Reaction

rxn releases energy as heat making the surroundings hotter as they absorb the heat

△Hrxn is negative

energy

The ability to do work or produce heat

Kinetic Energy

the energy an object has due to its motion, depends on mass and velocity

Potential Energy

energy due to position or composition

Joule (J)

SI unit of energy, 1 atm = 101.325 J

Heat (q)

the transfer of energy between two objects due to a temperature difference

Work (w)

force over a distance

state function

function of a property at its present state

system

part of universe we focus on

surroundings

everything else in the universe we are not focusing on

law of conservation of energy

1st law of thermodynamics

energy can be converted from one form to another but never created or destroyed, energy of universe is constant

Thermodynamics

the study of energy and its interconversions

Internal Energy (E)

the sum of kinetic and potential energy, E= q+w

How do you calculate work done on or by a system?

w= -P(external) x V(system)

how do you calculate the change in internal energy for a closed system

E(closed)= q+w

calculating heat from heat capacity

q = C(capacity) x T(temp)

calculating heat from specific heat capacity

q= m C(specific) x T

calculating heat from molar heat capacity

q= n(moles) C(molar) x T

Amplitude

the height of a wave's crest

wavelength (λ)

Horizontal distance between the crests or between the troughs of two adjacent waves

speed (c)

The distance an object travels per unit of time

Frequency (v / hz)

period

A horizontal row of elements in the periodic table

interference

the combination of two or more waves that results in a single wave

wave-particle duality

electrons and light can behave as both a wave and a particle

de Broglie wavelength

λ=h/mv

the wavelength associated with a moving particle

Bohr's theory of a hydrogen atom

Electron can exist in any one set of discrete states (energy levels) and can move from one to another by emitting or absorbing energy

difference of electron ground state and electron excited state

Heisenberg uncertainty principle

states that it is impossible to determine simultaneously both the position and velocity of an electron or any other particle

Describe the quantum mechanical model of the atom

The nucleus contains protons and neutrons. The electron cloud is a visual model of the probable locations of electrons in an probability of finding an electron is higher in the denser regions of the cloud.

Aufbau Principle

states that each electron occupies the lowest energy orbital available

periodic trends in atomic radius and ionization energy