Chemistry 2 Final Review

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list chemical bonds from strongest to weakest

ionic, covalent, hydrogen bonds, london dispersion, and van der waal

When you take something away from a system at equilibrium, the system...

shifts in such a way as to replace what you've taken away.

When you add something to a system at equilibrium, the system...

shifts in such a way as to use up what you've added.

A closed container of ice and water at equilibrium. The temperature is raised.
Ice + Energy -> Water

The equilibrium of the system shifts to the right to use up the added energy.

LeChatelier's Principle

When a system at equilibrium is placed under stress, the system will undergo a change in such a way as to relieve that stress

Q = (?Hv or ?Hf)(n)

Q is the total heat in or out, n is the number of moles, and ?Hv or ?Hf are the molar enthalpies of vaporization and fusion

Increase in pressure leads to...

an increase ?Hv and an increase in boiling point

Decrease in pressure leads to...

a decrease in ?Hv and a decrease in boiling point

Equilibrium

the dynamic condition in which BOTH processes occur at EQUAL rates

Boiling Point

the temperature at which the vapor pressure equals the atmospheric pressure.

water molar enthalpy of vaporization

40.79 kJ/mol

water molar enthalpy of fusion

6.009 kJ/mol

specific heat of water

4.18 J/g

Phase Change Diagram

Types of Crystals:

ionic, covalent networks, covalent molecular, and metallic

ionic

group 1 or 2 metals combined with group 16 or 17 non-metals
properties: hard & brittle, poor electricity conduction, high melting point, poor heat conduction, strong bonds

covalent network

unit cells are bonded covalently with neighboring unit cells
properties: hard & brittle, high melting point, poor electricity/heat conduction, and STRONG BONDS between stoms

Covalent molecular

held together by dipole and dispersion forces (weak bonds)
properties: soft, low melting point, poor electricity conduction, and poor heat conduction

metallic

metal cations surrounded by a "free-flowing" set of valence electrons
properties: variable hardness & melting point, good conductor of electricity and of heat

Network Solids

Composed of strong directional covalent bonds that are best viewed as a "giant molecule". They are brittle (non-flexible), they do not conduct heat or electricity, and are carbon, silicon-based

amorphous solids

glasses and plastics (not arranged in a regular pattern)

absolute vs gauge pressure

Gauge pressure is the pressure measured relative to atmospheric pressure. Gauge pressure is positive for pressures above atmospheric pressure, zero at atmospheric pressure, and negative for pressures below atmospheric pressure. The total pressure is commo

Solubility Trends

What is special about gas solubility?

When the pressure is increased and the temperature is decreased the gas solubility is increased.

What are the three types of mixtures?

solutions, colloids, suspensions

solution

a homogeneous mixture of two or more substances in a single phase

suspension

If the particles in a solvent are so large that they settle out unless the mixture is constantly stirred or agitated, the mixture is called this

colloids

Particles that are intermediate in size between those in solutions and suspensions form mixtures known as colloidal dispersions, or simply colloids

Miscible

Liquids that dissolve freely in one another in any proportion (liquids that can dissolve in each other)

Immisicible

Liquids that are not soluble in each other

Molarity

- M = moles(n) of solute/liters(volume) of solution
- mol/L

Molality

- m = moles(n) of solute/kg(mass) of solvent
- mol/kg

What is osmosis?

the diffusion of water through a semipermeable membrane and the water goes from a low concentration to a high concentration

Colligative Properties of Solutions

vapor pressure lowering, boiling point elevation, freezing point depression

Arrhenius acid

a chemical compound that increases the concentration of hydrogen ions, H+, in aqueous solution

Arrhenius base

a substance that increases the concentration of hydroxide ions, OH?, in aqueous solution

Bronsted-Lowry acid

is a molecule or ion that is a proton donor

Bronsted-Lowry base

a molecule or ion that is a proton acceptor

Lewis acid

an atom, ion, or molecule that accepts an electron pair to form a covalent bond

Lewis Base

an atom, ion, or molecule that donates an electron pair to form a covalent bond

conjugate acid

The species that is formed when a Br´┐Żnsted-Lowry base gains a proton is the conjugate acid of that base

conjugate base

the species that remains after a Br´┐Żnsted-Lowry acid has given up a proton is the conjugate base of that acid

Weak Acids

An acid that releases few hydrogen ions in aqueous solution

Strong Acids

one that ionizes completely in aqueous solution

Weak vs Strong Acids:

When copper is dissolved in acid, what gas is released?

nitrogen dioxide gas

What two things mix together to make a buffer?

Acid & a salt of that acid (one has to be weak) and a base & a salt of that base (one has to be weak)

pH equation

pH = -log[H+]

What do you do to get the concentration when given the pH?

10^-pH

kw=?

[H3O+ ][OH- ] = 1.0 x 10^-14 M

Calculating [H3O+] and [OH-]

pH

the negative of the common logarithm of the hydronium ion concentration, [H3O+]

pOH

the negative of the common logarithm of the hydroxide ion concentration, [OH?]

Hydrolysis

A reaction between water molecules and ions of a dissolved salt

Finding k (aA + bB -> cC + dD)

k = [C]^c [D]^d / [A]^a [B]^b

What is included when writing the chemical equilibrium expression?

gases, not solids or liquids

What happens when ka is higher?

The acid is more soluble

What happens when a substance gives off a lot of energy when it is forming?

It is stable

What are enthalpies?

They are in molar (per mole of formation or per mole of reactant)

enthalpy of reaction

the quantity of energy transferred as heat during a chemical reaction

entropy

S, can be defined in a simple qualitative way as a measure of the degree of randomness of the particles, such as molecules, in a system

What happens when more articles are around or there are more spaces for them to go?

There is more entropy

Qualitative predictions - entropy will be positive IF there is...

melting, vaporization, sublimation, temperature increase, and an increase in the number of gas molecules

Energy Diagram

The rate of reaction is influenced by the following factors:

nature of reactants, surface area, temperature, concentration of reactants, and the presence of catalysts

How does the rate determining step help determine the rate law?

It will be based upon its coefficients

order

The power to which a reactant concentration is raised

order of reaction

the sum of the reactant orders

Identify the oxidation and reduction half reactions in the following redox reaction
Zn + Cu^2+ -> Zn^2+ + Cu

Oxidation

Processes in which the atoms or ions of an element experience an increase in oxidation state are oxidation processes

reduction

Processes in which the oxidation state of an element decreases are reduction processes

What makes a redox reaction a redox reaction?

The change in oxidation states, so if there is no change in the oxidation states in the reaction then it is not a redox