Practice Test Review (Chemical and Physical) Flashcards
How do you find molarity?
Find the total mass of the compound and divide by that compounds molar mass (g/mol), which is calculated via the periodic table
What does absorption of salt in the blood cause?
The blood to become hypertonic, causing osmosis of water out of the cells
What is alpha decay?
An alpha particle (two protons, two neutrons, 2+ charge) is emitted
What is beta-minus decay?
What is beta-plus decay?
Beta-plus: Proton is converted to a neutron, a beta+ particle (positron) is emitted.
Beta-minus: Neutron is converted into a proton, a beta- particle (electron) is emitted.
What is gamma decay?
A gamma ray (high energy photon) is emitted from an excited nucleus.
What is electron capture decay?
A nucleus “grab” an electron, which changes a proton into a neutron.
What is a half-life?
Time required for one-half of the parent isotopes in a sample to decay into daughter isotopes
General MCAT Tip:
When asked a specific question about research design or execution (not testing over knowledge), choose an answer that can be inferred from the text, rather than an obscure guess that makes sense
What is chiral?
A carbon attached to four different groups.
How do you find the amount of stereoisomers for a molecule?
2^n the amount of chiral centers
What do l and d mean in terms of chirality?
Compounds that produce clockwise (+) rotation of light are dextrorotatory, compounds that produce counterclockwise (-) rotation of light are levorotatory
What are boiling chips used for in distillations?
Provide nucleation sites that give the liquid a place to start forming bubbles to prevent superheating
What is vacuum distillation used for in distillations?
Lower the boiling points of the substances to be distilled. (Reduces the atmospheric pressure)
When does boiling occur?
What the vapor pressure of the substance equals the atmospheric pressure.
In distillation procedures, which compound boils off first?
The one with the lower boiling point.
How do you compare the boiling/melting point between two compounds?
Functional groups with hydrogen bonding have higher boiling/melting points. Nitrogen containing compounds have medium melting/boiling points.
How do you determine formal charge?
valence electrons - sticks - dots.
How do you determine the amount of valence electrons?
The main group number (Main groups are numbered 1 - 8, skipping over the transition metals)
How do you calculate gravitational potential energy of a mass?
Mass * g * height
How do you calculate kinetic energy of a mass?
1/2 Mass * velocity^2
How do you calculate maximum speed achieved by a mass?
Set potential energy (Mass * g * height) = kinetic energy (1/2 Mass * velocity^2) and solve for velocity
How do you find stereo centers?
Carbon bonding to four different substituents, may need to look several positions away from the stereo center to find a difference in substituents
What is the preferred ion configuration of many elements determined by?
The electron configuration of the nearest noble gas; elements will gain or lose electrons until they have the same valence electron configuration as this noble gas
What is the equation for torque?
T = rFsin(theta), F is force applied from the fulcrum, d is the distance between the force and the fulcrum, and theta is the angle between the lever arm and the force that is applied
(if the force is applied perpendicular to the rotation then sin(90) = 1)
What is the equation for velocity?
distance/time
What is a titration?
The process of finding the concentration of an unknown solution by reacting it with a solution of known concentration.
What is the equivalence point of a titration curve? How can you find it on the titration curve?
When the Molarity base * Volume base = Molarity acid * Volume acid
Halfway along the steep portion of the titration curve
How do competitive inhibitors affect Vmax and Km?
Noncompetitive?
Uncompetitive?
Competitive- No change to Vmax (maximum velocity), but Km (concentration needed to reach half of Vmax) is increased.
Noncompetitive- Vmax is decreased, Km stays the same.
Uncompetitive- Vmax and Km are both decreased
What is an IC50 value?
Half Maximal Inhibitory Concentration - represents the concentration of a drug that is required for 50% inhibition in vitro
What are the unit prefixes milli, micro, nano, pico?
Milli: 10^-3
Micro: 10^-6
Nano: 10^-9
Pico: 10^-12
What are the three Newton laws?
1st: An object remains at rest unless acted upon
2nd: Total sum of focus acting on an object is equal to mass*acceleration
3rd: When body A exerts a force on body B, body B exerts an equal an opposite force on body A
How does N2 function as a gas? What is it used for?
It is very inert, can be used as a good artificial atmosphere when working with reactive reagents
What is the makeup and structure of acetone?
C3H6O, trigonal planer with a =O and 2 -CH3
How do you calculate total resistance from individual resistances?
1/Rtot = 1/R(one) + 1R(two) + …
What is Ohm’s law, and what is the equation for power?
Voltage(V) = Current(I) * Resistance(R) Power(P) = Current(I) * Voltage(V)
What are the three simple power equations?
P = IV, P = I^2R, P = V^2/R
What is the reagent LiAlH4 used for?
reduction (gain of hydrogen or loss of oxygen or other electron withdrawing species)
What is the reagent O3 used for?
Cleavage of alkenes
What is the reagent H2 with Pd used for?
Very strong reduction to alkane
What is the reagent KMnO4 used for?
Very strong oxidizing agent
Molecules with names that end in -one, -en, or -ol are what?
steroids
What are the three major functions of steroid hormones?
Salt, sex, and sugar
Describe the 6 Primary enzyme classes: oxidoreductase transferase lyase hydrolase ligase
oxidoreductase- oxidation-education reactions
transferase- group transfer
lyase- break molecules into two smaller molecules without using water or redox reactions
hydrolase-cleavage of a molecule using water
ligase- two substrates are stitched together while giving off a water
What do peaks at 3000 and 1700 indicate in IR spectroscopy?
3000 - OH
1700 =O
Which pair of amino acids creates disulfide linkages?
C-C (Cysteine)
A light entering a more dense medium (index of refraction >1.00) will have what relationship between angel of incidence and angle of refraction?
Angle of refraction will be lower than angle of incidence
When can total internal reflection result?
When a ray of light begins in a higher index material and reaches a boundary with a lower-index one (starts in water and moves towards air)
How many valence electrons does a single bond represent for the central atom? Lone pair?
Single bond counts for one valence electron. Lone pair counts for two
What does RSE stand for? What does it indicate?
Relative stabilization energy. The lower the value the greater the stabilization
What is the relationship between deltaH, deltaS, and spontaneity?
DeltaH (-) + DeltaS (+) = always spontaneous
DeltaH (+) + DeltaS (-) = never spontaneous
DeltaH (-) + DeltaS (-) = spontaneous at low temperature
DeltaH (-) + DeltaS (+) = spontaneous at high temperature
What is a capacitor? Resistor? Battery/Galvanic cell?
Capacitor- Used to store charge
Resistor- impedes charge
Galvanic cell- uses a spontaneous redox reaction to produce an electrical potential
What are the function of microtubules?
vesicle transport and organelle positioning, formation of spindle
