Chem/Physics MCAT

what is the equation for the root mean square velocity of gas particles in a substance

isothermal

word that signifies no temperature change

Adiabatic

a word that signifies no heat exchange (Q=0)

Isobaric

a word that signifies constant pressure

pyridine

the presence of a hemiketal

How can you determine if a cyclic sugar was a ketone?

structure of triglyceride

Archimedes’ Principle equation

homogenous catalysts

catalysts that are in the same phase as the reactants

Acid chlorides > Acid anhydrides > Esters > Carboxylic acids > Amides

What is the order of relative reactivities of carboxylic acids and their derivatives?

Alcohol (OH) IR Peak

Deep U shape around 3000-3600 cm -1

Carboxylic Acid (OH) IR Peak

broad peak overlapping with C-H bonds, giving it a jagged appearance at 2800-3200 cm-1

Carbonyl (C=O) IR Peak

sharp and deep peak at 1700-1750 cm-1

Amine or Amide (N-H) IR Peak

one or two sharp peaks at 3300-3500 cm-1

triglycerides

One glycerol molecule bonded to three fatty acid chains through ester linkages

gas-liquid chromatography

an analytical technique used to separate a complex mixture into its individual components based on two main factors:

1. boiling point- lower BP moves through the system faster

2. affinity to the stationary phase

Both of these affect the Retention Time

E=hf

equation relating the energy of a photon to its frequency where h is Planck’s Constant

f = v/λ

equation relating frequency, wavelength, and speed of a photon

avogadro’s number

6 × 10^23

E˚

Electrochemical potential calculated as the difference between the reduction potentials of the cathode and anode reaction
if E˚ is positive, the reaction is spontaneous

Reaction quotient (Q)

tells you where the reaction is right now.

When Q < Keq, the reaction favors the products

When Q > Keq, the reaction favors the reactants

When Q=Keq, the reaction is in equilibrirm

Spectator Ion

Ions that do not participate in the chemical reaction and remain unchanged in solution

Arrhenius base

earliest description of a base that is describe as increasing the concentration of hydroxide (OH^-) ions when in solution

Bronsted-Lowry base

type of base that is described to act as a proton acceptor

Lewis Base

a type of base that donates a pair of electrons

Bernoulli’s Principle (Velocity vs. Static Pressure)

In a moving fluid, as velocity increases, static pressure decreases but dynamic pressure increases

dyanamic pressure

The kinetic energy per unit volume of a fluid in motion that increases with velocity

Formula: ½ pv²

Hydrostatic Pressure

The pressure exerted by a fluid at equilibrium at a specific point, caused by the weight of the fluid above it due to gravity.

Formula: P = pgh

Infrared (IR) spectroscopy

a method used to identify specific functional groups present on an unknown molecule. Group frequencies are vibrations that are associated with certain functional groups. A molecule can be identified when its vibrational frequencies on an IR spectrum are compared to known spectra values.

UV-Vis spectroscopy

This technique detects conjugated pi systems and metal-to-ligand charge transfer species, both of which exist here

the field lines get denser

how does the appearance of electric field lines change as the field gets stronger

lewis acid

a molecule that donates an electron pair

lewis base

a molecule that accepts an electron pair

Bronste- lowry acid

a molecule that donates a hydrogen atom

Pd/C

a catalyst used in hydrogenation reactions:

The Pd surface physically pulls the H-H bond apart, making the hydrogens reactive.

Because the alkene "docks" onto a flat metal landing pad, both hydrogens are delivered to the same face of the double bond simultaneously. —> Syn addition

In a DC circuit, a fully charged capacitor acts as an open circuit (a broken wire) and there is no current flowing through —> the bulb is off

A DC battery is connected in a single series loop to a resistor (light bulb) and a capacitor. What is the state of the bulb in the Steady State, and what is the physical reasoning?

Keq

refers to the ratio of products to reactants at equilibrium of the reaction

diamagnetic materials

materials with only paired electrons that are slightly repelled by a magnetic field

paramagnetic materials

materials that have unpaired electrons with random spins, and thus, are weakly attracted to magnetic fields

ferromagnetic materials

materials in which the spins of the electrons in adjacent atoms tend to align parallel to each other. This alignment creates regions called domains, where the magnetic moments are all aligned. When the material is magnetized, these domains line up, resulting in a strong magnetic effect

first ionization energy

how much work an external force must do to steal an electron away from the nucleus's positive pull.

This energy increases as atomic radii decreases and effective nuclear charge decreases

principle quantum number

Describes the size and energy level of the orbital (also called the shell) written as positive integers (n = 1, 2, 3 …).

As n increases, the orbital becomes larger and the electrons spends more time away from the nucleus, increasing its energy

angular momentum quantum number (azimuthal)

Describes the shape of the orbital (the subshell)

l = 0 —> s orbital

l = 1 —> p orbital

l = 2 —> d orbital

l = 3 —> f orbital

Because electronegativity is defined as an atom's ability to attract electrons within a chemical bond.

Since Noble Gases have a full octet, they are chemically inert and rarely form bonds, making their "attraction" to shared electrons effectively zero or undefined

Why are Noble Gases (He, Ne, Ar) typically excluded from the Pauling Electronegativity Scale?

Stokes shift

is the difference in wavelength (or frequency) between the light that a molecule absorbs and the light that it eventually emits.

When a fluorescent molecule (a fluorophore) absorbs a photon, it gains energy. When it later releases that energy as light, the emitted photon almost always has less energy than the one that was absorbed

inverse - as energy increases, wavelength decreases (shorter)

what is the relationship between energy and wavelength?

Increasing length increases resolution because SEC relies strictly on the physical path through porous beads

In Size-Exclusion Chromatography (SEC), how does increasing the column length affect the separation of proteins

thin layer chromotography

a lab method of separating molecules by their polarity

TLC stationary phase

a thin layer of polar absorbent like silica gel

TLC mobile phase

a liquid solvent that moves up the stationary phase via capillary action to separate components

Retention Factor

a numerical value used in chromatography to describe how far a specific compound travels compared to how far the solvent (the mobile phase) travels.

A high retention value indicates a fast sample that troubles far up the stationary phase

-ate

suffix for the standard oxyanion

-ite

suffix for an oxyanion with one fewer oxygen that the -ate form

per-

prefix used when an oxyanion has one more oxygen that the -ate form

hypo-

prefix when an oxyanion has one fewer oxygen than the -ite form

-ic acid

what happens to -ate when the molecule becomes an acid?

-ous acid

when happens to -ite when the molecule becomes an acid

N = n x M

what is the equation for Normality?

Galvanic cells

a cell set up to house spontaneous redox reactions in a way that generates or uses electrical energy to create a current
Anode: negative

Cathode: positive

E˚ = positive

Daniell cell

a system in which two half-cells are connected by a salt bridge, which allows spectator ions to travel in between half-cells  → serves to balance the charges as the reaction progresses

electrolytic cells

a system in which electrical energy is used to drive a nonspontaneous redox reaction

anode: positive

cathode: negative

E˚ is negative

charges are attractive

what does a negative electrostatic force indicate?

bohr effect

It explains how certain conditions in the body—specifically, high levels of CO2 and acidity (low pH) —cause hemoglobin to release oxygen more readily to the tissues that need it most

venturi effect

is a principle in fluid mechanics where a fluid's velocity increases and its static pressure decreases as it flows through a constricted section of a pipe.

Pascal’s law

states that when pressure is applied to a confined, incompressible fluid, that pressure change is transmitted undiminished to every part of the fluid and to the walls of its container.

a more spontaneous process

What does a low/negative ∆H value signify?

a more spontaneous process

What does a higher/more positive ∆S value signify?

Hammond’s Postulate

states that the structure of a transition state resembles the species (reactant, intermediate, or product) to which it is closest in energy.

In Endothermic Reactions, the transition state resembles the products

In Exothermic Reactions, the transition state resembles the reactants

Vitamins B and C

Which vitamins are water-soluable?

Vitamins A, D, E, and K

Which vitamins are lipid-soluble?

Vitamin K

The vitamin associated with coagulation — functions to modify clotting factors in the liver

Vitamin A

the vitamin that functions as a precursor for retinal

Vitamin D

The vitamin that functions to regulate calcium and phosphate absorption in the GI tract

Vitamin E

this vitamin functions to Eliminate radicals and protect the cells from oxidative damage

Vitamin C

this vitamin is an antioxidant and is known for collagen synthesis

Vitamin B

This vitamin acts as a coenzyme or a precursor to coenzymes (NAD+, FADH+, etc)

Dyenin

a motor protein that walks towards the minus end of the microtubules, which is oriented towards the center of the cell. Movement toward the center of the cell is described as retrograde. (Dying in the middle of the ring)

Kinesin

a motor protein that is responsible for anterograde transport in cells (Kicking things out)

˚incidence > ˚critical

this results in total internal reflection

The value of an equilibrium constant is ONLY changed by temperature, not concentration.

What is the “golden rule” of equilibrium constants?

Downfield

in what direction do proton signals move if they experience deshielding effects?

geometric isomers

These have the same connectivity (the atoms are attached to the same neighbors) but differ in their spatial arrangement around a rigid bond (cis and trans)

constitutional isomers

These have the same connectivity (the atoms are attached to the same neighbors) but differ in their spatial arrangement around a rigid bond (like a double bond or a ring).

gamma particles

high energy photons that have 0 charge

alpha particles

a helium nucleus with a charge of +2

beta particles

these particles are electrons with a charge of -1

positrons

these particles have a charge of +1

half-equivalence point

the point during titrations at which the pH is equal to the pKa of the solution being titrated because the concentrations of the acid and base are equal (log(1)=0)

inverse: high Ka = low pKa = strong acid

relationship between Ka and pKa?

isolated system

a system that exchanges neither energy nor mass with its surroundings

closed system

a system in which there is energy exchange but not mass exchange with the surroundings

open system

a system that exchanges both mass and energy with its surroundings

latent heat

heat released or absorbed during a phase change

strong nuclear force

the force that holds the protons together in the nuclear > the electromagnetic force that repels the positive charges

binding energy

the energy input needed to break the nucleus apart into its components

mass defect

the difference in expected mass of the nucleus and the actual mass due to some of the mass being transformed into nuclear binding energy

photoelectric effect

when protons hit the surface of a metal, they excite metallic electrons to a higher energy state, causing them to move farther away from the atomic nucleus and be emitted

work function

the minimum amount of energy required to eject an electron from the metallic atomic nucleus = the energy of the incident photon

alpha decay

results in the emission of 2 protons and 2 neutrons, causing the atomic number to decrease by 2 and the atomic weight by 4

beta minus decay

the decay that occurs when a neutron is converted into a proton an electron is emitted