Mcat Gen Chem

Front 1

Average molecular speeds

Back 1

Front 2

Gibbs Free Energy

Back 2

If G is negative --> RXN is spontaneous
If G is positive --> RXN is non-spontaneous
If G is 0 --> Equilibrium (G=TS)

Front 3

Where do the distinct lines form an atomic emission spectra come from?

Back 3

Upon falling back to ground state an electron emits a photon of a characteristic wavelength (lambda)

Front 4

What phase is the absorption spectra used to identify elements in?

Back 4

The gas phase

Blue Shift - Moving closer
Red Shift - Moving Away

Front 5

Hund's Rule

Back 5

orbitals filled with half spin first

Front 6

Paramagnetic Vs Diamagnetic

Back 6

Paramagnetic - Compounds with unpaired electrons have slight attraction to magnetic fields

Diamagnetic - Compounds with out unpaired electrons are slightly repelled from magnetic fields

Front 7

Formal Charge

Back 7

Group in Periodic table - BARS - DOTS (covalent bonds - unpaired electrons)

Front 8

Energy of a light quanta

Back 8

E = hf or E = hv

h = plank's constant
f = frequency

Front 9

Speed of light

Back 9

Front 10

Electromagnetic energy of photons

Back 10

Front 11

For every value of N (principle quantum number) there is _______ value (capacity) to hold electrons

Back 11

2n^2

example: For n=1 2(1)^2 = 2 electrons

Front 12

Gas constant

Back 12

R = 8.314 J/mol*K

R = 0.0821 L*Atm/mol*K

Front 13

Volume of a gas at STP

Back 13

22.4 L

Front 14

Total pressure is a sum of what

Back 14

All the partial pressures

Pt = Pa + Pb + Pc + ...Pn

Front 15

Partial pressure

Back 15

Pa = PtXa

Pt = Total pressure
Xa = mol fraction (# mol A / # mol Tot)

Front 16

Pauli Exclusion Principle

Back 16

No two electrons can have the same set of quantum numbers

Front 17

Aufbau Principle

Back 17

Governs how orbitals are filled.

Front 18

Electron Affinity

Back 18

Energy released when an electron is added to the outer shell of an atom

Increases Left to Right across periodic table

Front 19

Reaction Quotient "Q"

Back 19

Q = [product] / [reactant]

Front 20

Normality equation

Back 20

Normality is # equivalents/L

You get normality by nultiplying the (# equivalents/mol * molarity)

Remember M1V1 = M2V2

Front 21

Energy of C-H bonds

Back 21

The more S character a bond has the lower in energy it is.

ALKYNE < ALKENE < ALKANE

ALKYNE - 50% S
ALKENE - 33.3% S
ALKANE - 25% S

Front 22

Arrhenius Acid/Base

Back 22

Acid - produces H
Base - produces -OH

All about water

Front 23

Bronsted-Lowry Acid/Base

Back 23

Acid - Donates H
Base - Accepts H

Works for organic

Front 24

what is an amphoteric species

Back 24

One that can act as an acid or a base

Front 25

pH

Back 25

Front 26

Logarithm math (with pH)

Back 26

Front 27

Small Ka and Kb values indicated a strong or weak acid or base?

Back 27

Small Ka = weak acid

Small Kb = weak base

K is [products]/[reactants]

Front 28

Ka (conj. acid) X Kb (conj. base) = ????

Back 28

= Kw = 10^(-14)

Front 29

equivalent weight

Back 29

the gram equivalent weight is the mass of a compound that produces one equivalent (mole of charge)

ex: H2SO4 is divalent, molar mass = 98g/mol. Since it's divalent the equivalent weight is 98/2 = 49g.

Thus 49 g will give one mole of charge (H+)

Front 30

Titration equation

Back 30

NaVa = NbVb

N = normality
V = volume

Front 31

In titration when does the indicator change color?

Back 31

At the end point, NOT the equivalent point

Front 32

TITRATION (titrand & titrant)

Strong Acid and Strong base

Back 32

Equivalence point = pH 7

Front 33

TITRATION (titrand & titrant)

Weak Acid & Strong Base

Back 33

Equivalce point = pH > 7

Front 34

TITRATION (titrand & titrant)

Weak base & Strong Acid

Back 34

equivalence point = pH < 7

Front 35

TITRATION (titrand & titrant)

Polyprotic Base & Strong Acid

Back 35

The tirtation of acidic or basic amino acids will look similar but with 3 equivalence points.

Front 36

Buffer

Back 36

Either a mixture of:

1) A weak acid and its salt
ex: acetic acid & Sodium Acetate
2) A weak base and its salt
ex: ammonioa & ammonium chloride

Front 37

Henderson-Hasselbalch Equation

Back 37

Used to estimate the pH or pOH of a solution in the buffer region where concentrations are approx. equal

The one above is for a weak acid buffer solution. Reverse it for a weak base.

Front 38

Arrhenius Acid/Base

Back 38

Acid: H donor

Base: OH donor

Front 39

Bronsted-Lowry Acid/Base

Back 39

Acid: H Donor

Base: H Acceptor

Front 40

Kw

Back 40

Equilibrium constant of autoionization of water

NOTE all "K" are ratio of [products]/[reactants]

Kw = Ka x Kb

all K are temp dependent

Front 41

Normality

Back 41

Equivalents per Liter

Norm = Molarity x eq/mol

Front 42

Cathode is always the site of

Back 42

Reduction!!

RED CAT AN OX

Front 43

Emf (E)

Back 43

If E > 0 then spontaneous (opposite of Gibbs)

Front 44

Gibbs Energy (cell)

Back 44

Front 45

Gibbs Cell related to Keq

Back 45

Front 46

Total Charge transferred in electrolysis

Back 46

I x t = n x F

I = current
t = time
n = number of moles of electrons
F = Faraday ~ 100,000

Front 47

Ortho Para (activating) directing (pic)

Front 48

Ortho & Para activating directors

[pic]

Back 48

Front 49

Meta de-activating directors

[pic]

Back 49