General Chemistry II Comprehensive Final Exam Study guide

Ionic

Intermolecular forces: ion-ion forces

Properties: brittle, hard, high-melting

Examples: NaCl, KBr, MgCl2

Molecular

Intermolecular forces: dispersion forces, dipole-dipole forces, hydrogen bonds

Properties: soft, low-melting, nonconducting

Examples: H2O, Br2, CO2, CH4

Covalent network

Intermolecular forces: covalent bonds

Properties: hard, high-melting

Examples: C (diamond), SiO2

Metallic

Intermolecular forces: metallic bonds

Properties: variable hardness and melting point, conducting

Examples: Na, Zn, Cu, Fe

Simple cubic

Stacking pattern: a-a-a-a

Coordination number: 6

Space used (%): 52

Unit cell: primitive-cubic

Body-centered cubic

Stacking pattern: a-b-a-b

Coordination number: 8

Space used (%): 68

Unit cell: body-centered cubic

Hexagonal closest-packing

Stacking pattern: a-b-a-b

Coordination number: 12

Space used (%): 74

Unit cell: (noncubic)

Cubic closest-packing

Stacking pattern: a-b-c-a-b-c

Coordination number: 12

Space used (%): 74

Unit cell: face-centered cubic

Molarity (M)

Moles of solute/liters of solution

Mole faction (X)

Moles of component/Total moles making up the solution

Mass percent

(Mass of component/total mass of solution) x 100%

Parts per million (ppm)

(Mass of component/total mass of solution) x10^6

Parts per billion (ppb)

(Mass of component/total mass of solution) x10^9

Molality (m)

Moles of solute/mass of solvent (kg)

Molarity (M)

Units: mole solute/L solution

Advantages: useful in stoichiometry, by volumes

Disadvantages: temperature-dependent, must know density to find solvent mass

Mole fraction (X)

Units: none

Advantages: temperature-independent, useful in special applications

Disadvantages: measure by mass, must know density to convert to molarity

Mass %

Units: %

Advantages: temperature-independent, useful in small amounts

Disadvantages: measure by mass, must know density to convert to molarity

Molality (m)

Units:

Advantages: temperature-independent, useful in special applications

Disadvantages: measure by mass, must know density to convert to molarity

Henry's Law

Solubility = kp

Colligative properties

In comparing the properties of a pure solvent with those of a solution:

- the vapor pressure of the solution is lower

- the boiling point of the solution is higher

- the freezing (or melting) point of the solution is lower

- the solution gives rise to osmosis, the migration of solvent molescules through a semipermeable membrane

Van't Hoff factor

i = moles of particle in solution/moles of solute dissolved

Integrated rate law for a zeroth-order reaction

[A]t = -kt + [A]0

K= -(slope)

Integrated rate law for a first-order reaction

ln ([A]t/[A]0) = -kt

K= -(slope)

Integrated rate law for a second-order reaction

1/[A]t = kt + 1/[A]0

K= slope

A compound is soluble if it contains one of the following cations

Li+, Na+, K+, Rb+, and Cs+ (Group 1A cations)

NH4+ <—- ammonium cation

A compound is soluble if it contains one of the following anions

Cl-, Br-, I- (halide anions) except Ag+, Hg22+, and Pb2+ halides.

No3-, ClO4-, Acetate, So4- except

Sr2+, Ba2+, Hg22+, and Pb2+ sulfates

What is the pH at the equivalence point of a weak acid-strong base titration?

pH>7, basic solution

What is the pH at the equivalence point of a Strong acid-strong base titration?

pH=7, neutral solution

What is the pH at the equivalence point of a Strong acid-weak base titration?

pH<7, acidic solution

Kn equals

1/[H30+][OH-]

pH at first equivalence point

pKa1+pka2/2

If the initial ion product is greater than Ksp then what will happen?

An ionic compound will precipitate

If the initial ion product is less than Ksp what will happen?

No solid ionic product will precipitate.

If a solution goes up in temperature what is the sign for enthalpy?

- delta H

If a solution goes down in temperature what is the sign for enthalpy?

+ delta H

If IP < Ksp, the solution is:

The solution is unsaturated and precipitation will not occur

If IP > Ksp, the solution is:

The solution is supersaturated and precipitation will occur.

If IP=Ksp, the solution is:

The solution is saturated and equilibrium already exists.

Entropy change upon volume change of a gas

Delta S = nR ln(Vfinal/Vinital)

Entropy change upon volume change of a gas

Delta S = nR ln(P initial/p final)

What is the third law of thermodynamics?

The entropy of a perfected ordered crystalline substance at 0k is zero.

What is the first law of thermodynamics?

In any process, spontaneous or non-spontaneous, the total energy of a system and its surroundings is constant.

What is the second law of thermodynamics?

In any spontaneous process, the total entropy of a system and its surroundings always increases.

If delta S total is greater than zero then the reaction is

Spontaneous

If delta S total is less than zero then the reaction is

Non-spontaneous

If delta S total = zero, the reaction mixture exists at

Equilibrium

All reactions proceed spontaneously in the direction that _______________ the entropy of the system plus the surroundings

Increases

When an exothermic reaction happens what happens to the entropy of the surroundings?

The surroundings gain heat and thus entropy increases.

When an endothermic reaction happens what happens to the entropy of the surroundings?

The surroundings lose heat and entropy decreases.

If delta g is less than zero, then the reaction is

Spontaneous

If delta g is greater than zero, then the reaction is

nonspontaneous

If delta g equals zero, then the reaction is

at equilibrium

if H is negative and S is positive

G is negative, and the reaction is spontaneous at all temperatures.

if H is positive and S is negative

G is positive, and the reaction is non-spontaneous at all temperatures.

If H and S are both negative

then G is spontaneous at low temperatures where delta H outweighs TS

and non-spontaneous at high temperatures where TS outweighs H

If H and S are both positive

Then G is spontaneous at high temperatures where TS outweighs H

and non-spontaneous at low temperatures where H outweighs TS

Standard State conditions

-Solids, liquids, and gases in pure format 1 atm

-Solutes at 1M concentration

-at a specified temperature, usually 25 degrees Celsius.

Free energy change under Nonstandard state conditions

Delta G = Delta G (standard) + RT ln Q

Relationship between standard Free-Energy change and equilibrium Constant

Delta G = -RT lnK

Relationship between the standard free energy change and the equilibrium constant of reaction

If Delta G <0, Lnk >0, K >0 and the equilibrium mixture is mainly products

If Delta G >0, Lnk<0, K<1 and the equilibrium mixture is mainly reactants

If Delta G = 0, Lnk =0, K=1 and the equilibrium mixture contains comparable amounts of reactants and products.

Electrons in a galvanic cell move away from the __________________ and towards the _________________

Anode, towards the cathode

The force that pushes electrons from the anode and towards the cathode is the?

EMF (electromotive force), also known as cell potential (E) or the cell voltage.

What does one joule equal in terms of coulombs and volts?

One coulomb times one volt

One amphere equals?

One coulomb divided by one second

One watt equals?

one joule divided by one second

What is an electronic instrument that measures cell potential?

A voltmeter

What the equation for the relationship between free-energy change and cell potential?

Delta G = -nfe

-N is the number of moles of electrons transferred in the reaction

-E is cell potential

-F is the faraday constant (96,500 C/ Mole e-)

What is the standard cell potential?

The standard cell potential is the cell potential when both reactants and products are mixed in their standard states- Solutes at 1M concentrations, gases at 1 atm of pressure, solids and liquids in pure form, with all at a specified temperature (usually 25 degrees C).

What measuring tool can also be regarded as a "free-energy meter"? This tool when measuring a standard cell potential also indirectly measures standard free energy.

A voltmeter.

How is the standard enthalpy of formation of a substance expressed?

It is expressed relative to an arbitrary reference point where delta H of formation = OkJ/mol for constituent elements in their standard state.

If the free energy change for a reaction is negative, then the reaction is?

Spontaneous. The greater the negative value of delta G, the greater the tendency for the reaction to occur.

What is S.H.E?

S.H.E is the standard hydrogen electrode. It is used as a reference electrode and is assigned an arbitrary potential of zero volts. It can serve as either a cathode or an anode in a galvanic cell.

Whenever the direction of a half-reaction is reversed, the sign of E must also be reversed. Thus the standard potential of the oxidation half reaction is the ________________ of the standard reduction potential.

Negative

The process of using an electric current to bring about a chemical change is called what?

Electrolysis

What is a fuel cell?

A galvanic cell in which one of the reactants is a fuel such as hydrogen or methanol.

How does acid strength increase with a hydroxide group (OH-)?

Acid strength increases with increasing oxidation number of the atom to which an OH group is attached. Electron density shifts from the OH group to the attached atom, the weakening the O-H bond, increasing its polarity, and facilitating proton transfer to a solvent water molecule.

Lewis Acid

lone pair acceptor

Lewis base

Lone pair donor

Ligand

An electron pair donor in a metal ion complex

Monodentate ligands

Are ligands that bond using an electron pair of a single donor atom.

Polydentate ligands

Ligands that bond through electron pairs on more than one donor atom.

chelating agents

A polydentate ligand that is capable of occupying two or more sites in the coordination sphere.

At the temperature where a phase change occurs both phases coexist at equilibrium and this means that Delta G is what?

Zero.

Clausius-Clapeyron equation

ln(p1/p2)=(-ΔHvap/R)(1/T2-1/T1)

simple cubic unit cell

-Coordination # 6 and 52% space used

-each layer is stacked on top of the previous layer perfectly

-there are eighths (one in each corner) for a total of ONE atom in each unit cell.

A=2R

Body centered cubic unit cell

-Coordination # 8 and 68% space used

-Each layer is offset from the layer before it. Arrangements duplicate themselves every other layer.

-There are eighths (one in each corner) and one full atom in the center for a total of TWO atoms in the unit cell.

A= (Square root (16/3)) R

Face Centered Cubic (FCC) unit cell (also known as cubic closest packing)

-Coordination # 12 and 74% of space is used

-Each layer is offset from the layer before. Arrangements duplicate themselves every third layer.

-There are eighths (one in each corner), and six halves (one for each face of the cube) for a total of FOUR atoms in the unit cell

A= (square root of 8) R

How many picometers in a meter?

1.0 x10^12

How many picometers in a centimeter

1.0 x10^10

Density equation for Unit packing arrangements

D=ZM/S^3 Na

z= # of atoms in cube

M=molar mass

S= edge length

Na= Avogadro's #

Corner atoms

1/8 an atom (8 corners)

edge atom

1/4 an atom (12 edges)

Face atom

1/2 an atom (6 faces)

Center atom

1 whole atom (1 center)

What is vicosity?

A measure of a liquids resistance to flow. Viscosity increases with increasing inter-molecular forces.

What is surface tension?

The resistance of a liquid to spread out and increase its surface area. More IMF means more surface tension.

What is vapor pressure?

In a closed container, liquid molecules evaporate and the resulting increase in pressure is called vapor pressure. Vapor pressure increases as temperature increases because more molecules have sufficient energy to overcome IMF and enter the gas phase.

Amorphous solids

Solids whose particles are not arranged in a regular pattern. Randomly arranged.

Crystalline Solids

Solid who's particles are arranged in a regular pattern.

types of crystalline solids: Ionic solids

Solids who's particles are ions