Chem 130 Exam 3

Strong acid

Dissociate completely to form H+ and an anion

HCl

HBr

HCIO3

H2SO4

HNO3

HCIO4

HI

Weak Acids

Partially dissociate to form H+ and an anion

HF

H3PO4

H2CO3

Ex:

CH3COOH(aq) + H2O(l) = CH3COO^_ (aq) + H3O^+ (aq)

Strong Bases

Dissociate to completely form OH^- and a cation

LiOH

NaOH

KOH

RbOH

CsOH

Ca(OH)2

Sr(OH)2

Ba(OH)2

Weak bases

Partially react with water to form OH^- and a cation

NH3(aq) + H2O(l) = NH4^+(aq) + (OH)^- (aq)

NH3

Mg(OH)2

Amines

Electrolytes

Salts

Bases

Acids

Nonelectrolytes(examples)

Sugars, alcohols, hydrocarbons

Oxidation states rule 1

Element is in elemental form

C2, O2, P4, C(s), S8

Oxidation state rule 2

.Monatomic ion equals its charge

Cl^- = -1

Oxidation rule number 3

Some elements have common oxidation numbers used as reference

Group 1 metals NA^+ = +1

Group 2 metals Ca²+ = +2

Hydrogen = usually +1

Hydrides (metal-H) = -1

Fluorine = -1

Oxygen = usually -2

Peroxides(-1) & superoxides possible

Cl/Br/I = -1

oxidation rule number 4

Sum of oxidation numbers equals the overall charge of molecule/ion

Oxidation rule number 5

Shared electrons are assigned to more electronegative atom. More electronegative atom will have more negative oxidation number.

‘Strong electrolytes

Good conductors

Weak electrolytes

Poor conductors

Nonelectrolytes

nonconductors( do not conduct electricity)

‘Electrolytes.

substances that dissolve in water and dissociate into ions

Absorbs Energy

Energy is required to disrupt intermolecular interaction

Vaporization: Liquid to Gas

Fusion(melting): Solid to Liquid

Sublimation: Solid to Gas

Releases energy

Energy is released when intermolecular interactions are formed

Condensation: Gas to Liquid

Freezing: Liquid to Solid

Deposition: Gas to Solid

Heat Capacity

Heat required to raise the temp. of a substance by 1K(or C)

Different for each phase

Specific heat capacity: heat capacity per gram, Cs = heat transfered(q)/mass * temp. change

Molar heat capacity: heat capacity per mol, Cm= heat transfered(q)/moles* temp. change

Calorimetry

Experimental measure of heat flow

Measure the energy changes involved in physical + chemical processes

q = Cm * n * change in temp.

q = Cs * m *change in temp.

Combustion Reactions

Uses O2, makes CO2 + H2O

Combination Reactions

Two things become one

Decomposition Reaction

One thing becomes elements

Double Displacement Reactions

Precipitate

Weak or Non-electrolyte

Gas

Single Displacement: Redox

Transfer of electrons

Oxidation= loss of electrons

Reduction= gain of electrons

Oxidizing agent= substance that causes oxidation(it itself is reduced)

Reducing agent= substance that causes reduction(it itself is oxidized)

Endothermic

A constant pressure in which value of q is positive

A process in which kinetic energy in the system is converted to potential energy

A process in which heat is absorbed by the system

A process in which enthalpy increases

A process in which temperatures decreases

Exothermic

A constant pressure process in which the value of q is negative

A process in which temperature increases

A process in which enthalpy decreases

A process in which heat is transferred to the surroundings

A process in which potential energy in the system is converted to kinetic energy

Enthalpy

Reflects a system’s capacity or potential to transfer heat