MCAT General Chemistry Part 2 Flashcards
How does the kinetic molecular theory define a gases pressure?
A gases pressure is due to the collisions of the molecules with the walls of the container and all collisions are elastic
Because all molecules of a gas move at a constant speed between collisions and the collisions are elastic, the molecules of gas experience___
NO intermolecular forces
The average kinetic energy of a gas molecules is directly proportional to ___
Absolute temperature (in Kelvin) of the sample
The hypothesis that equal volumes of different gases at the same temperature and pressure contain the same number of particles
Avogadro’s hypothesis
A statement of the relationship between the pressure and volume of a constant amount of gas at constant temperatures
P = 1/V
Boyle’s Law
The process by which a gas escapes through a pinhole into a region of lower pressure
Effusion
The theory that states heat is associated with the thermal motion of particles, taking into account the important assumptions that individual gas molecules take up no volume and collisions between gas molecules are perfectly elastic
Kinetic-molecular theory
A gas that deviates from the behavior predicted by the ideal gas law. Real gases differ from the expected behavior of an ideal gas (lower V and P) for two reasons:
- The force of attraction between the particles in a gas are not zero
- The volume of the particles in a gas is not zero
Real gas
A reaction in which the rate is proportional to the concentration of a single reactant raised to the first power rate = k[A]
first-order reaction
used to describe the relationship between the rate of a step in a chemical reation and the concentration of one of the reactants consumed in that step
Order
What three things affect and determine the reaction rate?
- How frequently the reactant molecules collide
- The orientation of the colliding molecules
- Their energy
A blend of two or more metallic elements
Alloy
The process in which a bulk solid or liquid breaks up into individual molecules or ions diffuse throughout a solvent
Dissolution
Why are solids and liquids not included in equilibrium constants or expression?
Their concentration does not change
The value of the equilibrium constant (Keq) is constant at a given __
temperature
If the concentrations of reactants and products is at equilibrium then Q =
Keq
A system at equilibrium will try to neutralize any imposed change in order to reestablish equilibrium
Le Chateliers principle
The solubility of gases in liquid tends to ___ with increasing temperature
Decrease
The solubility of gases in liquids tends to ___ with increasing pressure
Increase
All group 1 elements and ammonium (NH4+) are ___
soluble
All nitrate (NO3-), perchlorate (CLO4-) and acetate (C2H3O2-) are___
soluble
All silver (Ag+) lead (Pb2+/4+) and mercury (Hg2+) are ___ unless they are part of nitrates, perchlorates, or acetates
Insoluble
The extent to which a salt will dissolve in water can be determined from its __
solubility product constant Ksp
The __ is the reaction quotient for a solubility reaction
Qsp ionic product
If Qsp < KsP
more salt can be dissolved
If Qsp = Ksp
Solution is saturated
If Qsp > Ksp
Excess salt will precipitate
A compound that dissociates when it dissolves in water to give the H+ ions
Arrhenius acid
A compound that dissociates when it dissolves in water to give the OH- ion
Arrhenius base
Any molecule or ion that can donate an H+ (proton)
Bronsted-Lowry acid
Any molecule or ion that can accept an H+ (proton)
Bronsted-Lowry base
The amount of acid or base a buffer solution can absorb without significant changes in pH
buffer capacity
What are the 6 most common strong acids with a Ka above 1?
Hydroiodic acid Hydrobromic acid Hydrochloric acid Perchloric acid HClO4 Sulfuric acid H2SO4 Nitric Acid HNO3
What are the common strong bases (memorize these)
Group 1 hydroxides (NaOH)
Group 1 oxides (example: Li2O)
Some group 2 hydroxides= Ba(OH)2, Sr(OH)2, Ca(OH)2
Metal amides: NaNH2
The conjugate base of a strong acid__
has no basic properties
example:
HCl +H20 -> H30+ + Cl-
The conjugate base of a weak acid___
is a weak base
The site of oxidation in a galvanic or electrolytic cell
Anode
The electrode towards which anions flow through a salt bridge
Anode
A set of electrochemical cells connected in series or parallel
Battery
The site of reduction in a galvanic or electrolytic cell
Cathode
The electrode in an electrochemical cell towards which cations flow through a salt bridge
Cathode
A measure of the driving force behind an electrochemical reaction
Cell-potential
A type of electrochemical cell that has identical reactants in each half reaction, but at different concentrations, thus driving a weak electrical current
Concentration cell
A process in which an electrical current is used to drive a nonspontaneous chemical reaction
Electrolysis
A nonspontanoeous electrical cell in which electrolysis is done
Electrolytic cell
A statement of the relationship between the amount of electric current that passes through an electrolytic cell and the amount of product formed during electrolysis.
The amount of chemical change is proportional to the amount of electric current that flows through the cell
Faraday’s law of electrolysis
An electrochemical cell that uses a spontaneous chemical reaction to do work, synonymous with voltaic cell
Galvanic cell
A measure of the driving force behind an electrochemical reaction that is reported in units of volts
Potential
Anions from the salt bridge of the galvanic cell go to the ___ and cations travel in the opposite direction
Anions from the salt bridge go to the anode
Cations from the salt bridge go to the cathode
Tables on the MCAT for half-reaction potentials usually only given for ___ reactions
Reduction, to get the oxidation, just flip the sign
The free-energy change for a redox reaction in which cell voltage is E is given by the equation
G = - nFE
n is number of moles of electrons transferred
F is faraday constant which is 96,500 coulombs
E is cell voltage V
The redox reaction in a cell will be spontaneous if the cell voltage is __
positive because that will make G negative, spontaneous
The more negative the reduction potential
The weaker the reactant is as an oxidizing agent, and the STRONGER the product is as a reducing agent
The more positive the reduction potential,
the stronger the reactant is as an oxidizing agent, and the weaker the product is as a reducing agent
A ___ uses an external voltage source, such as a battery, to create an electric current that forces a nonspontaneous redox reaction to occur
Electrolytic cell
How do you solve for for the amount of electricity (in coulombs, C) that flowed through a cell?
Q = IxT
Q = charge
I = current (amps)
T (time)
