Chemistry 2 (the final boss)

free energy

(helps predict whether a process will occur spontaneously) the minimum energy required for a nonspontaneous reaction.

ex. Gibbs free energy

lattice energy

(ionic solids and gaseous ions) the energy released when the gaseous ions combine to form an ionic solid

It's a measure of the strength of the forces holding the ions together in the solid crystal lattice

kinetic energy

the energy an object has due to its motion. the average kinetic energy is the same for any ideal gas at a given temperature no matter the mass.

activation energy

the minimum energy required to initiate a reaction

ionization energy

is the amount of energy required to remove one mole of electrons from one mole of gaseous atoms or ions to form positive ions

• The first ionization energy is the energy to remove the first electron from a neutral atom.

• The second ionization energy is the energy to remove a second electron from a +1 ion, and so on

• Atomic radius – Larger atoms have lower ionization energy.

• Nuclear charge – More protons = higher attraction = higher ionization energy

If a sample is inside a closed system with no form changes to the sample (solid to liquid etc), the energy and entropy

remain constant

if a sample dissolves in water and the temperature drops, that means

it absorbs heat (the process is endothermic)

low lattice energy =

exothermic

high lattice energy =

endothermic

if dissolution is endothermic

increasing temperature favors greater solubility (le chatliers principle)

if dissolution is exothermic

Increasing temperature decreases solubility (le chatliers principle)

Keq and G when a reaction is spontaneous

Keq > 1 deltaG’’ < 0

+delta H

Endothermic

-deltaH

Exothermic

Alpha decay

4/2

Beta Decay

0/+1

Gamma Decay

0/0

Positron emission

0/-1

Electron capture

0/-1

oxidation–reduction reaction

electrons are transferred between substances

solid composed of macromolecules held together by strong bonds

covalent network solids (covalent bonds) ex. SiO2 (they share an electron)

A solid composed of positive and negative ions held together by electrostatic attractions

(-) + (+) ex. KNO3

A solid composed of atoms held together by delocalized electrons

Metallic Solid ex. Fe

A solid composed of molecules held together by intermolecular dipole-dipole interactions

Lewis structure results in dipole moment. ex. HCl

A solid composed of molecules held together by intermolecular london forces

Lewis structure doesnt result in dipole moment. ex. I2, CO2

Diamond

full of carbon molecules covalently bonded together = cvalent network solid

As we move down the nitrogen group (Group 15) boiling point

increases. except for in NH3 bc of hydrogen bonding

The critical point is

the highest temperature and pressure where the substance may exist as discrete liquid and gas phases

in a phase diagram the line separating the solid from the liquid phase may have a positive or negative slope due to

density

Negative slope: Liquid denser than solid

Positive slope: Solid denser than Liquid

What can affect bp of a liquid in a container

sealed container (pressure) . volume has no affect, a vaccum would decrease pressure

surface tension

is the property of a liquid that allows it to resist an external force due to the cohesive forces between its molecules

if a question asks why a molecule of a different isomer has a stronger bond of molecules than the other its probably bc of

hydrogen bonding

relative solubilities in water

anything else < ends/starts w OH < OH on both sides

condensation

gas to liquid

deposition

gas to solid

sublimation

solid to gas

fusion

solid to liquid

vaporization

liquid to gas

ionic bond strength

• Charge of the ions (higher charge = stronger bond)

• Size (radius) of the ions (smaller = stronger bond)

• Lattice structure and energy

molarity

M = mol solute /1L solution

molality

m= mol solute /1kg/L solvent

molar mass

mass of solute/moles of solute

Rate law: Zero order

• rate = k

• A=-kt + initial

• [A] vs t

• slope -k

• units: mol/L / sec

Rate law: First order

• rate = k[A]

• In(final) = -kt +In(initial)

• ln [A] vs t

• slope: -k

• units: sec

Rate law: Second Order

• rate = k[A]²

• 1/(final) = kt +1/(initial)

• 1/[A] vs t

• slope: +k

• units: L mole/ sec

k, the rate constant, depends only on

temperature.

• Decrease temp = increase k

• increase temp = decrease k

What can speed up a chemical reaction?

Catalyst and high temperature

Higher reaction rate can indicate

high concentrations of reactants, low activation energy (quicker to reach = quicker reaction rate)

slow reaction rate indicates

high activation energy (takes longer to reach = slow)

the energy difference between the reactants and the transition state is

activation energy

In step reactions, which step is the one that matters?

the last slow step

titration curves are what shaped?

S shaped

because titration curves are S shaped, if a weak base is mixed with a strong acid over time, the pH will

drop slowly at first, then rapidly decreases

bases

accept a proton

acids

donate a proton

if a chemical reaction is endothermic and temperature is increased and volume is decreased (heat added to reactants) will this produce more product?

Yes because the equilibrium will shift towards products (right)

If the K value is less than one, the reaction will be

shifting left (acids on right have to be stronger)

If the K value is more than one, the reaction will be

shifting right (Acids on left have to be stronger)

If i want to increase the solubility of a substance i would add nitric acid (a strong acid) to a

weak base

Half life equations (k given)

Final = Initiale^-kt

Half life equations (no k given)

Final = initial (1/2)^(t/t1/2)

When finding a rate law of a reaction by being given a table

use general rate law equation and compare experiment 2 and 1, then 3 and 1. if the answer is 1, its first law, if the answer doubles, its second law. if the rate changes throughout the experiments the rate law cant be 0.

ex. experiment 2: k[A]^m[B]^n / experiment 1: k[A]^m[B]^n

General rate law equation

Rate = k[A]^m[B]^n

ICE table equation

x²/M-x (ignore -x if ksp is low enough)

ph equations

• pH= pKa + log (A (base) /HA (Acid))

• pH= -log [H3O] or [Ka]

pKa

-log(ka)

Kc=

[A]^x(coefficient) [B]^x(coefficient) / [C]^x(coefficient) [D]^x(coefficient)

going from current to mass of substance

current (A) —> charge (C) (may have to use oxidation number) —> 1mole / 96500 —> moles of substance —> mass of substance

Ecell=

reduction+oxidation