MCAT General Chemistry Part 2

Question 1

How does the kinetic molecular theory define a gases pressure?

Answer 1

A gases pressure is due to the collisions of the molecules with the walls of the container and all collisions are elastic

Question 2

Because all molecules of a gas move at a constant speed between collisions and the collisions are elastic, the molecules of gas experience___

Answer 2

NO intermolecular forces

Question 3

The average kinetic energy of a gas molecules is directly proportional to ___

Answer 3

Absolute temperature (in Kelvin) of the sample

Question 4

The hypothesis that equal volumes of different gases at the same temperature and pressure contain the same number of particles

Answer 4

Avogadro’s hypothesis

Question 5

A statement of the relationship between the pressure and volume of a constant amount of gas at constant temperatures

P = 1/V

Answer 5

Boyle’s Law

Question 6

The process by which a gas escapes through a pinhole into a region of lower pressure

Answer 6

Effusion

Question 7

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

Answer 7

Kinetic-molecular theory

Question 8

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:

1. The force of attraction between the particles in a gas are not zero
2. The volume of the particles in a gas is not zero

Answer 8

Real gas

Question 9

A reaction in which the rate is proportional to the concentration of a single reactant raised to the first power rate = k[A]

Answer 9

first-order reaction

Question 10

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

Answer 10

Order

Question 11

What three things affect and determine the reaction rate?

Answer 11

1. How frequently the reactant molecules collide
2. The orientation of the colliding molecules
3. Their energy

Question 12

A blend of two or more metallic elements

Answer 12

Alloy

Question 13

The process in which a bulk solid or liquid breaks up into individual molecules or ions diffuse throughout a solvent

Answer 13

Dissolution

Question 14

Why are solids and liquids not included in equilibrium constants or expression?

Answer 14

Their concentration does not change

Question 15

The value of the equilibrium constant (Keq) is constant at a given __

Answer 15

temperature

Question 16

If the concentrations of reactants and products is at equilibrium then Q =

Answer 16

Keq

Question 17

A system at equilibrium will try to neutralize any imposed change in order to reestablish equilibrium

Answer 17

Le Chateliers principle

Question 18

The solubility of gases in liquid tends to ___ with increasing temperature

Answer 18

Decrease

Question 19

The solubility of gases in liquids tends to ___ with increasing pressure

Answer 19

Increase

Question 20

All group 1 elements and ammonium (NH4+) are ___

Answer 20

soluble

Question 21

All nitrate (NO3-), perchlorate (CLO4-) and acetate (C2H3O2-) are___

Answer 21

soluble

Question 22

All silver (Ag+) lead (Pb2+/4+) and mercury (Hg2+) are ___ unless they are part of nitrates, perchlorates, or acetates

Answer 22

Insoluble

Question 23

The extent to which a salt will dissolve in water can be determined from its __

Answer 23

solubility product constant Ksp

Question 24

The __ is the reaction quotient for a solubility reaction

Answer 24

Qsp ionic product

Question 25

If Qsp < KsP

Answer 25

more salt can be dissolved

Question 26

If Qsp = Ksp

Answer 26

Solution is saturated

Question 27

If Qsp > Ksp

Answer 27

Excess salt will precipitate

Question 28

A compound that dissociates when it dissolves in water to give the H+ ions

Answer 28

Arrhenius acid

Question 29

A compound that dissociates when it dissolves in water to give the OH- ion

Answer 29

Arrhenius base

Question 30

Any molecule or ion that can donate an H+ (proton)

Answer 30

Bronsted-Lowry acid

Question 31

Any molecule or ion that can accept an H+ (proton)

Answer 31

Bronsted-Lowry base

Question 32

The amount of acid or base a buffer solution can absorb without significant changes in pH

Answer 32

buffer capacity

Question 33

What are the 6 most common strong acids with a Ka above 1?

Answer 33

``` Hydroiodic acid Hydrobromic acid Hydrochloric acid Perchloric acid HClO4 Sulfuric acid H2SO4 Nitric Acid HNO3 ```

Question 34

What are the common strong bases (memorize these)

Answer 34

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

Question 35

The conjugate base of a strong acid__

Answer 35

has no basic properties example: HCl +H20 -> H30+ + Cl-

Question 36

The conjugate base of a weak acid___

Answer 36

is a weak base

Question 37

The site of oxidation in a galvanic or electrolytic cell

Answer 37

Anode

Question 38

The electrode towards which anions flow through a salt bridge

Answer 38

Anode

Question 39

A set of electrochemical cells connected in series or parallel

Answer 39

Battery

Question 40

The site of reduction in a galvanic or electrolytic cell

Answer 40

Cathode

Question 41

The electrode in an electrochemical cell towards which cations flow through a salt bridge

Answer 41

Cathode

Question 42

A measure of the driving force behind an electrochemical reaction

Answer 42

Cell-potential

Question 43

A type of electrochemical cell that has identical reactants in each half reaction, but at different concentrations, thus driving a weak electrical current

Answer 43

Concentration cell

Question 44

A process in which an electrical current is used to drive a nonspontaneous chemical reaction

Answer 44

Electrolysis

Question 45

A nonspontanoeous electrical cell in which electrolysis is done

Answer 45

Electrolytic cell

Question 46

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

Answer 46

Faraday's law of electrolysis

Question 47

An electrochemical cell that uses a spontaneous chemical reaction to do work, synonymous with voltaic cell

Answer 47

Galvanic cell

Question 48

A measure of the driving force behind an electrochemical reaction that is reported in units of volts

Answer 48

Potential

Question 49

Anions from the salt bridge of the galvanic cell go to the ___ and cations travel in the opposite direction

Answer 49

Anions from the salt bridge go to the anode | Cations from the salt bridge go to the cathode

Question 50

Tables on the MCAT for half-reaction potentials usually only given for ___ reactions

Answer 50

Reduction, to get the oxidation, just flip the sign

Question 51

The free-energy change for a redox reaction in which cell voltage is E is given by the equation

Answer 51

G = - nFE n is number of moles of electrons transferred F is faraday constant which is 96,500 coulombs E is cell voltage V

Question 52

The redox reaction in a cell will be spontaneous if the cell voltage is __

Answer 52

positive because that will make G negative, spontaneous

Question 53

The more negative the reduction potential

Answer 53

The weaker the reactant is as an oxidizing agent, and the STRONGER the product is as a reducing agent

Question 54

The more positive the reduction potential,

Answer 54

the stronger the reactant is as an oxidizing agent, and the weaker the product is as a reducing agent

Question 55

A ___ uses an external voltage source, such as a battery, to create an electric current that forces a nonspontaneous redox reaction to occur

Answer 55

Electrolytic cell

Question 56

How do you solve for for the amount of electricity (in coulombs, C) that flowed through a cell?

Answer 56

Q = IxT Q = charge I = current (amps) T (time)