Mcat Chem Terms

Front 1

What is the mass of an Electron? The charge?

Back 1

m = 9.11 x 10^-31 kg
C = -1.602 x 10^-19 C

Front 2

What is the mass of a proton? The charge?

Back 2

m = 1.67 x 10^-27 kg
C = 1.602 x 10^-19 C

Front 3

Thomson Experiment

Back 3

Plates perpendicular to the electron trajectory resulting in bends. He discovered the signs of the charges. Showed that protons and e had opposing charges.

Front 4

Positron

Back 4

Anti-electron. Same mass but opposite charge. Different from a proton.

Front 5

Neutrino

Back 5

Essentially massless particle with no charge

Front 6

Gamma Ray

Back 6

Photon. Photons do not bend in a field unless there is a change in medium.

Front 7

Muon

Back 7

Negatively charged but is 200 times the mass of an electron.

Front 8

1H isotope

Back 8

most abundant isotope

Front 9

2H Isotope

Back 9

Deutrium, used in proton NMR solvents

Front 10

3H

Back 10

Tritium, used in radio labelling experiments

Front 11

12C isotope

Back 11

most abundant

Front 12

13C isotope

Back 12

used in Carbon NMR

Front 13

14C isotope

Back 13

used in carbon sampling, since it undergoes decay

Front 14

235U isotope

Back 14

used in nuclear fission

Front 15

238U isotope

Back 15

most abundant isotope

Front 16

Mass Spectrometry Formula

Back 16

r = mv/qB

Front 17

Millikan Experiment

Back 17

He ionized an oil drop and suspended it. He deduced the charge of an electron/proton (1.6 x 10^-19C).

Front 18

Plum Pudding Model

Back 18

Proposed by Thomson in 1904 showing - plums in a + pudding

Front 19

Rutherford Experiment

Back 19

Gold foil experiment showed that gold atoms had a centralized nucleus (thought to be +) organized in a lattice manner. Disproved Plum Pudding.

Front 20

Particle Theory

Back 20

Atoms contain subatomic particles (more recent definition)

Front 21

Law of Definite Proportions (Proust s Law)

Back 21

The composition of a compound is related to the proportion of elements by mass. Stoichiometry.

Front 22

What differences in electronegativity tell you about the bond? (3)

Back 22

<1.5 = COVALENT
1.5< e < 2 = Polar Covalent
>2 = IONIC

Front 23

Avogadro's number

Back 23

6.022 x 10^-23

Front 24

Convert F to C.

Back 24

Tf = 9/5Tc + 32

Front 25

Convert C to F

Back 25

Tc = 5/9Tf - 32

Front 26

What is the difference between Density and Specific Gravity?

Back 26

Specific Gravity is the density relative to Water. no Units

Front 27

What is the dilution equation?

Back 27

m1v1 = m2v2<BR>Also, c1v1 = c2v2

Front 28

What is the concentration equation?

Back 28

n = cV

Front 29

Hygroscopic Salt. Eg?

Back 29

Used in combustion analysis that absorbs water but not C02. It grows in size to measure the mass of h20 made. eg. CaCl2, MgSO4

Front 30

MOLARITY vs MOLALITY. What is the adv of the latter?

Back 30

Molality = moles/kg of solution. Latter doesnt change with temp. Able to measure BP elevation and FP depression

Front 31

What is the key difference in determining the mass percent in a compound vs solution!!

Back 31

BI p. 1.22. The total mass is the mass of the solvent and the solute in solution questions. Dont forget.

Front 32

Mole Fraction

Back 32

The number of moles of substance/number of moles of compound

Front 33

What is the mass percent of C in CO2?

Back 33

27.3%

Front 34

What is the mass percent of H in H20?

Back 34

11%

Front 35

What is the volume of one molar gas at RTP? STP? What are the units?

Back 35

RTP: 24.5L
STP: 22.4L
L/mol

Front 36

What is the formula for pH

Back 36

pH = -log [H+]

Front 37

What is the Henderson-Hasselbach equation? use?

Back 37

pH = pKa + log ([con base]/[con acid]). Determining the pH of the buffer system.

Front 38

What is the formula for determining the pH of a weak reagent?

Back 38

pH = 0.5pKa - 0.5log[HA]

Front 39

Amphoteric

Back 39

The ability to act as both an acid or a base. eg. Water.

Front 40

What is the formula for the acid disassocation constant?

Back 40

Ka = [H30+][A-]/[HA]

Front 41

What is the strongest acid that we know?

Back 41

Perchloric Acid (HCLO4) (pKa of -10).

Front 42

Review the common names for the following: HNO3, H2SO4, HClO3. HNO2, H2SO3, HClO2.
HClO.

Back 42

Nitric, Sulfuric, Chloric.
Nitrous, Sulfurous, Chlorous.
Hypochlorous.

Front 43

What is the log of 2,3,5?

Back 43

0.3
0.5
0.7

Front 44

Recall that pH calc shortcut!

Back 44

-log[ 2 x 10^-3]
= log (10^3) - log 2
= 3 - 0.3
= 2.7

Front 45

What happens to a conjugate pair if the pH > pKa? pH < pKa?

Back 45

- Deprotonation
- Protonation

Front 46

What is the pKa range for carboxy acid? ammonium? pKa 2 of phosphoric acid? carbonic acid?
OR SEE p. 262.

Back 46

- 3-5
- 9 - 10
- 7.2
- 6.4

Front 47

What is the pKa of carboxy acid, phenol, alkyl ammonium cation?

Back 47

- 3-5
- 9.5 - 10.5
- 9 - 11

Front 48

What temperature unit do we use for Gas Laws/related?

Back 48

Kelvin

Front 49

Gas Pressure.
What 3 things affect this?

Back 49

The force per unit area exerted during collisions on THE WALL.
- Temperature, concentration, Volume of container

Front 50

Collision Frequency.
What 2 things affect?

Back 50

Related to GAS PRESSURE is the frequency of collision of particles both with each other and the wall
- Concentration and hence the mean free path and temperature

Front 51

Collision Force.
What 1 thing affects this?

Back 51

Related to GAS PRESSURE is the force exerted by the particle during the collision (IMPULSE).
- Increasing the temp only

Front 52

Mean Free Path

Back 52

The average distance that a particle must travel before it collides with another particle.

Front 53

Temperature in a GAS system

Back 53

the quanititative amount of the total kinetic energy in the system

Front 54

What kind of liquid is most ideal for a thermometer? Describe also the BP and the MP?

Back 54

Mercury: Water's density does not decrease uniformly. Also, more energy is required to increase the columm.
- We also want a huge difference in the MP and BP to maintain liquid form.

Front 55

What are the 4 aspects of the Kinetic Molecular Theory of Gases? BASICALLY the same for the IDEAL GAS THEORY

Back 55

- Volume of particles negligent
- Elastic Collisions
- No intermolecular forces
- Particles move in constant random translational motion.

Front 56

USE the KPMG to describe why the P of an ideal gas is maintained despite differing molecular masses (2)?

Back 56

Heavier the particle = less collision freq but higher collision force. Light particles are opposite. The two contrasting things cancel out each other.

Front 57

Boltzmann's Distribution.
How does increasing TEMP affect this graph?

Back 57

Describes the KE of particles over a wide range. (MEAN KE is to the right of the apex)
- The graph shifts to the right as temperature increases.

Front 58

What is the most ideal gas (element wise)? Why (2)?

Back 58

- HELIUM: one of the smallest (negligent volume)
- noble gas hence small intermolecular forces.

Front 59

What is the IDEAL GAS EQUATION?
What does the R stand for?

Back 59

PV = nRT
R = 0.0821 atm....

Front 60

What is the ultimate GAS FORMULA that relates all the laws together?

Back 60

P1V1/n1T1 = P2V2/n2T2

Front 61

What is the Vanderwaal's equation?
DELVE INTO THE REASONING BEHIND

Back 61

(Pobs + an2/V2)(Vcont - nb) = nRT
a = attractive constant (can be negative) (-) when repulsive.
b = bigness constant (always +)

Front 62

What is our statement regarding the Vanderwaal's equation?

Back 62

It's not about trying to make the value "ideal", but what must be done to the "ideal" calculations in order to reflect the "real" P and V values.

Front 63

Avogadro's Law played with what two factors?

Back 63

number of moles and volume.

V1/n1 = V2/n2

Front 64

Boyle's law?

Back 64

P1V1 = P2V2

Inverse graph that deviated towards the end...

Front 65

Charles' Law?
Describe the graph.

Back 65

P1/T1 = P2/T2
It levels off towards lower temperatures due to a phase change = where V with solid/liquids change less than gases.

Front 66

Dalton's Law of Partial Pressure

Back 66

(Mole fraction)(Total P) = partial pressure.

ALL THOSE PARTIAL PRESSURES MUST ADD UP TO TOTAL PRESSURE.

Front 67

What are the different units represent STANDARD PRESSURE!

Back 67

1 atm
760 mmHg
101.3 kPa

Front 68

Square Rooting a Decimal

Back 68

Beware the double decimal

Front 69

Piston vs rigid container

Back 69

In a piston, when temperature is increased, assume the volume increases! (changing the mean free path). In a rigid container, the volume is fixed despite temperature.

Front 70

What is the correlation between macro and micro of the following:
1. Temperature
2. Concentration
3. Pressure
4. Moles
5. Volume

Back 70

1. temp - Average KE
2. Conc - Mean Free Path
3. Collision force/frequency
4. Moles - molecules
5. Vol - container wall

Front 71

How does the mean free path change when concentration increases?

Back 71

Decreases. Since there are more particles the distance between each is lessened.

Front 72

Isotopic Enrichment

Back 72

By taking advantage of the differing effusion/diffusion rates, the faster will be more concentrated near the front while the heavier will be more concetrated in the back

Front 73

How do you determine the root mean square speed?
What is R? What are the units for T and m?

Back 73

u = [3RT/m]^1/2
R = 8.314
T is in K. m is in kg.

Front 74

Manometer.
What is the formula for pressure change depending on the height difference in this instrument?

Back 74

A manometer is the tube of mercury usually that displays pressure changes.
Delta P = (density)(g)(delta h).
If mercury, the height difference is equal to the pressure change

Front 75

What is the formula for relative velocities of two gases ITO m? How does it change when ITO T?

Back 75

v2/v1 = (m1/m2)^1/2
v2/v1 = (T2/T1)^1/2

Note the inversion that exists in the root mean square speed formula

Front 76

Effusion vs Infusion vs Diffusion

Back 76

Effusion - escape of particles through micro holes to the outside
Infusion - particles entering via micro holes from the outside
Diffusion - the spread of particles without the need of pores

Front 77

What is the density of mercury ITO g/cm^3 and kg/m^3?

Back 77

13.543 g/cm^3
13 543 kg/m^3

Front 78

Entropy

Back 78

Chaos

Front 79

How do the enthalpy and entropy values compare with sublimation, fusion, and vaporatization?

Back 79

Enthalpy/Entropy
Sub > Vap > Fusion

Front 80

Define the following terms regarding conditions?
1. Isothermal
2. Isobaric
3. Isochoric
4. Adiabatic

Back 80

1. Temp is maintained
2. Pressure is constant
3. Volume is constant
4. Heat neither enters nor leaves the system

Front 81

Triple Point

Back 81

The point where all 3 phases coexist

Front 82

Critical Point

Back 82

It is the highest temperature and pressure where a liquid can be observed. Beyond this point, it is indistinguishable.

Front 83

Normal Boiling Point

Back 83

The boiling point at 1 atm

Front 84

Vapor vs gas

Back 84

Gas is the actual phase while vapor refers to the gas that exists in equilibrium with a liquid state.

Front 85

What are some special characteristics about water and its density?

Back 85

Liquid form is more dense than the solid form (see negative slope).

It increases in density from 0 to 4, with 4 being the most dense. But the density does decreases from 4 - 100. (But still higher than solid)!

Front 86

Supercritical Fluids.
Note about its characterisitics and the density

Back 86

A fluid beyond the critical point (with characterisitics like liquid and gas).
It is the most dense at the bottom like a liquid, but fills up the entire cavity like a gas. The density is between liquid and gas.

Front 87

What is the oxidation state of any PURE element?

Back 87

0

Front 88

COMPLETE OXIDATION REVIEW

Back 88

- Loss of Electrons
- involved in catabolic reactions
- occurs always at the anode (metal dissolves)
- Gain bonds in O and lose H bonds

Front 89

Complete REDUCATION REVIEW

Back 89

- Gain of electrons
- involved in anabolic reactions
- occurs always at the cathode (metal is solidified)
- Gain bonds in H and lose in O

Front 90

Name the priority of Oxidation States

Back 90

H>Oxygen>Halogens!!
See X.Pa1.3

Front 91

What is the difference between acid-base reactions and redox reactions? (AT LEAST IN BRONSTED LOWRY)

Back 91

Only protons are transferred and not ELECTRONS - the oxidation state does not change.

Front 92

What are the general rules for balancing redox equations?
The Bridge method is faster than the one in high school

Back 92

1. Determine the oxidation state
2. identify the electrons being gained or lost
3. CROSS MULTIPLY the half reactions
4. Balance the charges by either adding H+ or OH- depending on the situation
5. Balance the additions with H2O

Front 93

How is balancing equations different between the NORM and REDOX Equations?

Back 93

Whenever you encounter anything remotely to redox, the purpose of balancing is to equate the number of electrons on each side! (seeing the charges on each side can help)

Front 94

in an emf table, the values usually represent? What does a more positive value mean?

What does this mean for oxidizing/reducing agents?

Back 94

Emfs are usually reductive potentials. The more positive the more likely to be reduced.

Therefore, HIGHER Reductive Potentials mean STRONGER OXIDIZING AGENTS. Lower Reductive Potentials mean STRONGER REDUCING AGENTS

Front 95

How can we use the periodic table to predict reduction potentials?

Alkali metals, transition metals, precious metals.

Back 95

Alkali/Alkaline want to lose that electron, hence they are readily oxidized. Halogens want to gain, hence they are likely reduced.

Transition metals have no pattenr.
Precious metals are the right portion of the transition metals like to be in their metallic state - therefore the ions of these metals readily reduce to return to their metallic state.

Front 96

How do you determine the emf of the reaction? Though the sign changes, when u reverse it, what happens when you multiply a coefficient to balance electrons?

Back 96

Add the emf of the reduction and oxidation.

When you multiply by a coefficient, DO NOT MULTIPLY THE emf values by the coefficient.

Front 97

how do you determine the FREE ENERGY in a cell? (unlike emf, this value is dependent on the number of values)

Back 97

DELTA G = -nF(Ecell)
F = 96500C/mole
n = number of electrons
**dont forget that negative!

Front 98

IN a electrochemical cell, which way do ELECTRONS always flow?

Back 98

Electrons also flow from the anode to the cathode. or from OXIDATION to REDUCTION.

Loss of Electrons moving towards Gaining Electrons

Front 99

What is the importance of the salt bridge in an electrochemical cell?

Back 99

SALT BRIDGES ARE NOT MADE OF SALT, but rather contain an aqueous solution contained in a membrane. These ions are used to balance out the ions that are produced/used on each end. THEY ARE NEEDED to complete the circuit or the battery will not run.

Front 100

Galvanic Cell vs Electrolytic Cell

Back 100

Galvanic cells involve spontaneous redox equations and do not require any voltage input. Electrolytic are non-spontaneous redox equations and do REQUIRE voltage input. electrolytic cells are basically Galvanic Cells in reverse.

Galvanics are used to discharge energy while eletrolytics are used to charge the cell.

Front 101

What is the convention for drawing galvanic cell? for electrolytic cell?

Back 101

Galvanics: the anode is drawn on the left. It is on the side of the shorter line while the cathode is on the side of the longer line. The e-flow goes to the right.

Electrolytic: everything in reverse to the Galvanic. NOTE THAT WHENEVER THE QUESTION INDICATES THAT THERE WAS A VOLTAGE INPUT, IT IS AUTOMATICALLY AN ELETROLYTIC CELL!!

Front 102

How do we increase the voltage of galvanic cell? What is the best way of the 2? What is the Equation that we can use to determine the actual difference in voltage?

Back 102

- by increasing the reactant cation (cathode) or by reducing the product cation (anode) - think lechatlier
- The BEST way is to have multiple cells in series, thus adding the electric potentials.
- NERST EQUATION:
Ecell = Estandard - RT/nFlnQrx
Q = [anode]/[cathode]. n = the number of electrons AFTER balancing!

Front 103

Why does the flashlight continue to work despite the batteries dying after use?

Back 103

once the batteries have cooled, the batteries will work for a bit since the equilibrium changes due to temp.

Recall that when the electrochemical cell reaches equilibrium, the battery dies.

Front 104

Though we can keep recharging the battery by switching between it being a galvanic cell and an electrolytic cell, what eventually erodes the battery?

Back 104

- Side reaction products eventually build up.
- Also, ENTROPY.

Front 105

What are dry cell alkaline batteries structured like?

Back 105

the graphite rod is the conducting material with paste of MnO2 and NH4Cl surrounding it. The paste is surrounded by zinc connected to a cap at the end of the battery. When connected in a circuit, it connects the zinc to the graphite rod, allowing the flow of electrons between zinc and MnO2.

Front 106

HOW DO FLUORESCENT TUBES WORK?

Back 106

Basically a parallel capacitator - with gaseous ions - when they move to one side, they collide and some light energy released. They have to have alternate currents! (think about it). therfore, fluos actually kind of work like strobe lights.

Front 107

Incandescent Light Bulbs.

Back 107

Using a thin filament of tungsten in a sphere that lacks a medium, light is generated. The lack of medium strengthens the light since heat can't be dissipated - also, if there was an inert gas in the sphere, it would build with pressure and explode due to temp increase.

Front 108

Why is tungsten used in light bulbs and x ray machins?

Back 108

They have the highest melting point of any conducting metal!

Front 109

Electrolysis

Back 109

Instead of trying to store energy like in electrolytic cells, the point of this is to create unfavorable compounds (water to elements). This are usually done in one cell, where a salt bridge is not needed! WORK OUT THE PRODUCTS OF ELECTROLYSIS OF WATER ON EACH ELECTRODE

Front 110

Why is electroplating important to catalysts?

Back 110

Eletroplating first involves coating a surface with another metal. In catalysts, we coat graphite with Pd or Pt for hydrogenation and such - the graphite allows the removal of the catalysts easily.

Front 111

Galvanizing

Back 111

A type of electroplating - used to protect surface with a METAL THAT WILL OXIDIZE EASIER.

Steel is important - the biggest component of steel is iron - therfore we need a metal with a lower reduction potential that iron like zinc to protect it!

Front 112

Coating

Back 112

This is another type of electroplating, but instead of coating the metal with more oxidizable metal, it is a metal that does not oxidize readily. ONLY WORKS FOR aluminum, chromium, and tin

Front 113

How do the kinetics differ between Sn2 and Sn1 reactions?

Back 113

Sn2 is dependent on both the concentration of the nucleophile and the electrophile (second order)
Sn1 is only dependent on the concentration of the electrophile!

Front 114

How does the rate of reactant depletion relate to product formation

Back 114

Delta [Products]/Delta t = -Delta [Reactants]/Delta t.
- the (-) value is to denote the difference
- THIS IS ASSUMING NO STOICHIOMETRIC DIFFERENCE. If there is, you know what to do,

Front 115

What is the graph representing the concentration of both the catalyst and intermediate over time?

Back 115

See II p.205.

Front 116

Steady state in kinetics

Back 116

The constant concentration of the intermediate!

Front 117

How can we experimentally study the reaction rate?
What are some advantage and dis of each.

Back 117

1. UV-visible spectroscopy
2. Gas Chromatography

1. Must be done quickly and in pulses since the light can add energy to the reaction. BUT this doesn't require the reaction to be "quenched. CAN be done IN VITRO (always the best)
2. This has to be "quenched" since the reaction can still be continuing in the pipette.

Front 118

Beer's Law

Back 118

Absorbence = Epsilon[C](length)
Epsilon = molar absorbity constant
[C] = concentration of species
length = usually 1

Front 119

UV Absorbence. What is the best peak to monitor? How should we adjust the wavelength?

Back 119

- the best peak to monitor is the peak with the greatest height (most likely that it will also have the greatest difference in height)
- we always want to adjust the wavelength to the largest peak wavelength. MUST be a REACTANT, since the product peaks are absent in the beginning.
PICTURE HOW U ABSORBENCE GRAPHS LOOK LIKE IN KINETICs

Front 120

In Depth Profile of ZERO ORDER REACTIONS

Back 120

- The concentration of the reactant does not change the rate.
- usually most common in catalyzed reactions - since the rate depends ont eh turnover rate of the catalyst.
- Graph of [] and t, the rate is constant (change in [] over time), but the half life decreases over time.
- LINEAR

Front 121

Coordination Number

Back 121

The number of atoms in contact with the one of interest

Front 122

What is happening at the Bohr Radius?

Back 122

The attraction is not equivalent to resistance. Rather the attraction is greater than resistance.

Front 123

Efficiency of any machine. In this case the balloon machine./

Back 123

Efficiency involves the method that wastes the least energy on movement/such.

In the case of that balloon machine: we wanted the least resistance from the water by decreasing the density in order to the machine to be able to run longer.

Front 124

During a common ion effect question: what do we assume for the ion concentration?

Back 124

Just assume that the substance completely disassociated for the sake of the common ion calculations.