Chemistry Flashcards Preview

MCAT > Chemistry > Flashcards

Flashcards in Chemistry Deck (54):
1

Ionic Bond

attractive force between positive and negative ions

2

Covalent Bond

sharing of electrons

3

Hybridization

sp3: single bonds; 4 half filled orbitals
sp2: double bond; 3 half filled orbitals
sp: triple bond; 2 half filled orbitals

4

Radioactive Emissions

Alpha: add Helium atom
Beta: removal of one electron
Positron: add one electron
Gamma: no changes, high frequency

5

Electrolytic Cell

nonspontaneous; electric current drives reaction

+ : anode/oxidation
- : cathode/reduction

6

Galvanic Cell

spontaneous; produces electric current

- : anode/oxidation
+ : cathode/reduction

7

Faraday's Constant

amount of reactants is equal to the current

96500 coulombs

8

Electromotive Force (EMF)

potential difference between two electrodes

9

Gibb's Free Energy

∆G = -nFE°cell
∆G = ∆H - T∆S
∆G=RTlnK

10

Rate Law

rate =k [A]^a [B]^b

11

Equilibrium Constant (Kc)

[M]products/[M]reactants

K << 1 = reactants favored
K >>1 = products favored
K = 1 equilibrium

12

Equilibrium Factors

concentration
pressure
temperature

13

Rate Factors

concentration
temperature
states of reactants
catalysts

14

First Law of Thermodynamics

energy is neither created nor destroyed

∆E = Q + W

15

Hesse's Law

the addition of enthalpy to find total reaction enthalpy

16

Entropy

measure of disorder

17

Zeroth Law of Thermodynamics

if two systems are linked and in equilibrium, adding a third system will also be at equilibrium

18

Third Law of Thermodynamics

pure crystalline substances have an entropy of 0 at 0 K

19

Second Law of Thermodynamics

entropy increases over time

20

Farenheit Conversion

℉ = 2℃ + 32

21

Arhenius Acid/Base

acid: increases H+ in aqueous solution
base: increases OH- in aqueous solution

22

Bronsted-Lowry Acid/Base

acid: proton donor
base: proton acceptor

23

Lewis Acid/Base

acid: electron acceptor
base: electron donor

24

Ionization of Water

Kw = [H30+] [OH-] = 1 X 10^ -14

25

Percent Ionization

Ka = x^2 / initial concentration

26

Ninja Trick

p [A X 10^-B] = (B-1).(10-A)

27

Endothermic Reaction

solid to liquid to gas

28

Indicators

pKa is +/- 1 of the desired pH

29

Avagadro's Number

6.022 X 10 ^23

30

Energy of an Electron

E= -Rh/n^2

31

Energy of a Photon

E = hc/ƛ

32

Heisenberg Uncertainty Principle

it is impossible to determine the momentum and position of an electron simultaneously

33

Quantum Numbers

n - shell
l - subshell - 0 to n-1
ml - orbital - (-l) to (l)
ms - spin - (-1/2) or (1/2)

34

Hund's Rule

orbitals are half full

35

Formal Charge

charge on an atom if electrons were shared equally

36

Chemical Geometry

linear - 180◦
trigonal planar - 120◦
tetrahedral - 109.5◦
trigonal bipyramid - 90◦, 120◦, 180◦
octahedral - 90◦, 180◦

37

State Funcitons

pressure, density, temperature, volume, enthalpy, internal energy, free energy, entropy

DEEP V FIT

38

Pressure Conversion

1 atm = 760 mmHg = 760 Torr = 101,325 Pa

39

Gas Laws

Boyles: PV
Charles: V/T
Gay-Lussac's: P/T
Avogadros: n/V
Combined: PV/T
Ideal: PV = nRT

40

Gas Deviations

Pressure: at high pressure volume of a gas is less than ideal

Temperature: at low temperatures a gas has smaller volume than ideal... when extremely low, volume is larger than ideal

41

Van der Waals equation of State

(P + n^2a/V^2) (V-nb) = nRT

42

Dalton's Law of Partial Pressure

sum of partial pressures equals total pressures

43

Average Molecular Speed

3/2 kT

44

Root mean square speed

u = sqrt (3RT/M)

45

Raoult's law

solutions are ideal

46

Effusion and Diffusion forumula

r1/r2 = sqrt (m2/m1)

47

Solubility Rules

- Group 1 and NH4+ cations are soluble
- Nitrate and Acetate anions are soluble
- Cl, Br, I are soluble except with Ag, Pb, and Hg
- SO4^2- anions are soluble except Ca, Sr, Ba, and Pb
- Metal oxides are insoluble except group 1 and Ca, Sr, and Br
- hydroxides are insoluble except group 1 and Ca, Sr, and Br
- carbonates, phosphates, sulfides, and sulfites and insoluble except group 1 and NH4+

48

titration equivalence point

ph = pKa

49

Henderson-Hasselbalch equation

pH = pKa + log (OH)/(H)

50

SN1 and SN2

- SN1: polar protic, favors tertiary, rate is dependent on rate limiting step, recemic products

- SN2: polar aprotic, favors methyl first, rate is dependent on nucelophile and rate limiting step, optically active and inverted, favored with strong nucelophile

51

Neucleophilic Characteristics

- charge: more negative
- electronegativity: less electronegative
- steric hinderance: smaller molecules
- solvent: aprotic

52

Best Leaving Groups

- weak bases
- large resonant groups
- large electron withdrawing groups

53

Purification Methods (not chromotography)

Simple distillation: separate on boiling point below 150 and at least 25 apart

Vacuum distillation: separate boiling point above 150

Fractional distillation: separate boiling point less than 25 apart

Recrystallization: separate solids by solubility in varying temperatures

Electrophoresis: separate macromolecules based on size and charge

54

Types of Chromotography

Thin layer: non polar solvent

Reverse phase: polar solvent

Column: non polar solvent, polar gel stationary phase, separates sample into components

Ion-exchange: non polar solvent, charged bead stationary phase, separate by charge

Size-exclusion: non polar solvent, porous beads stationary phase, separate by size

Affinity: non polar solvent, antibody bead stationary phase, purify a molecule

Gas: use gas and crushed metal to separate vaporized compounds

HPLC: non polar solvent, concentration gradient stationary phase, more precise than column