Chem Unit 4 Study Guide

Valence Bond Theory

overlap of atomic orbitals to form molecular bonds

What rule does valence bond theory follow

VSEPR theory

Where do valence electrons reside for valence bond theory

quantum (bonding and central) or hybrid orbitals (central)

Hybridization

combining orbitals to make a hybridization orbital in order for atoms to bond

What can you use to determine the hybridization orbital

electron geometry

What happens when the amount of bonds increases

the tendency to hybridize increases, the amount of full orbitals increases, and the stability increases

What hybridization does linear have

sp

What hybridization does trigonal planar have

sp2

What hybridization does tetrahedral have

sp3

What hybridization does trigonal bipyramidal have

sp3d

What hybridization does octahedral have

sp3d2

What type of bond is found in the hybridization orbital

sigma bonds

Where does the electron density go for sigma bonds

within the plane

What type of bond is found in unhybridized p and d orbitals

pi bonds

Where does the electron density go for pi bonds

over and under the plane

How many sigma and pi bonds do single bonds have

1 sigma 0 pi

How many sigma and pi bonds do double bonds have

1 sigma 1 pi

How many sigma and pi bonds do triple bonds have

1 sigma 2 pi

What is molecular orbital theory

a new molecular orbital bonding entity is created when bonding

What rules does molecular orbital theory follow

Pauli’s principle and Hund’s rule

Where are valence electrons found in molecular orbital theory

they’re delocalized/ everywhere in molecule

Linear combination of atomic orbitals

simplest combination of atomic orbitals to form molecular orbitals

What kind of combining do bonding orbitals have and what do they do

constructive combining, they stabilize the atom

What kind of combining do antibonding orbitals have and what do they do

destructive combining, they destabilize the atom

What is the equation for bond order

(antibonding-bonding)/2

What does higher bond order mean

a more stable atom

What does a bond order of 0 mean

it won’t form

What does unpaired electrons mean and what does unpaired mean

paired means it is diamagnetic and exhibits no magnetic properties

unpaired means it is paramagnetic and exhibits magnetic properties

Intramolecular forces (+ types)

the bonds between atoms; ionic, covalent, metallic

Intermolecular forces

attractive forces between molecules or ions

Are inter or intramolecular forces stronger

intramolecular forces

What effect does an increase in size have on intermolecular force strength

increases the strength of intermolecular forces

What effect does an increase in distance have on intermolecular forces

decreases the strength of intermolecular forces

What effect does an increase in charge have in intermolecular forces

increases the strength of intermolecular forces

What effect does an increase in intermolecular forces have on resistance to moving and breaking

increases the resistance to moving and breaking

What are the types of intermolecular forces from weakest to strongest

dispersion, dipole induced dipole, dipole dipole, hydrogen bonds, ion dipole, ion ion

What has dispersion forces and what only has dispersion forces

everything, nonpolar molecules

What contains dipole dipole interactions and down

polar molecules

What contains hydrogen bonds and down

molecules with H and F,O, or N

What contains ion dipole interactions

an ion and a polar molecule

What contains ion ion interactions

an ion and an ion/ ionic compounds

For dispersion forces, what effect does an increase in mass have on the strength

increases the interaction strength

For dispersion forces, what effect does an increase in the number of interactions have on the strength

increases the interaction strength

What is surface tension

the resistance to increasing surface area

What effect does an increase in strength of intermolecular forces have on surface tension

increases surface tension

What effect does an increase in temp have on surface tension

decreases surface tension

What effect does an increase in mass have on surface tension

increases surface tension

What is capillary action

the spontaneous rising of a liquid into a narrow tube

What two forces contribute to capillary action

cohesion (water sticking to water) and adhesion (water sticking to other stuff)

What does it mean when the meniscus is concave

adhesion > cohesion

What does it mean when the meniscus is convex

cohesion > adhesion

What is viscosity

a liquid’s resistance to flow

What effect does an increase in temp have on viscosity

decreases viscosity

What effect does an increase in mass have on viscosity

increases viscosity

What dissolves in polar solvent

polar and ionic solutes

What dissolves in nonpolar solvent

nonpolar solute

What states are changed in vaporization and is it endo or exo

liquid to gas, endothermic

What effect does an increase in temp have on vaporization rate

increases vaporization rate

What effect does an increase in surface area have on vaporization rate

increases vaporization rate

What effect does an increase in the strength of intermolecular forces have on vaporization rate

decreases vaporization rate

What states are changed in condensation and is it endo or exo

gas to liquid, exothermic

What effect does an open container have on condensation

decreases the rate of condensation

What effect does a closed container have on condensation

increases rate of condensation

What effect does an increase in intermolecular forces have on the rate of condensation

increases the rate of condensation

Volatile

evaporates easily

Nonvolatile

doesn’t evaporate easily

Heat of vaporization

amount of heat needed to vaporize one mole

Dynamic equilibrium

when 2 opposite processes have = rate

Vapor pressure

pressure exerted by vapor while in dynamic equilibrium

What happens to vapor pressure when the attractive force strength increases

vapor pressure decreases

Boiling point

when vapor pressure = external pressure and vapor bubbles form throughout the liquid

What effect does an increase of strength of intermolecular forces have on boiling point

increases boiling point

What is the Clausius- Clapeyron equation

ln(p2/p2)= (-ΔH/R)((1/T2)-(1/T1))

Heat of fusion

amount of heat absorbed to melt 1g of solid/ amount of heat released to freeze 1g of liquid

Heat of vaporization

amount of heat required to vaporize 1g of liquid/ amount of heat required to condense 1g of gas

Sublimation

solid to gas at the surface of the solid

Deposition

gas to solid

What do diagonal lines and horizontal lines represent in heating cooling curves

diagonal- change in temp w/ constant state, horizontal- change in state w/ constant temp

What is the triple point in phase diagrams

where all three phases exist at the same time

What is the space above liquid and gas

end of line is critical point and space is supercritical fluid

What properties does supercritical fluid present

properties of both liquid and gas

Crystalline solids

orderly geometric pattern

Amorphous solids

nonregular geometric patterns

What is a solution

A homogenous mixture of solute and solvent

Ionization

a solute dissolves in a solvent by breaking into ions

What interactions need to overcome which for a solution to form

solvent-solute needs to overcome solvent- solvent and solute- solute

How does ΔH hydration compare to ΔH solution in endothermic solutions

|ΔH hydration| < |ΔH solution|

How does ΔH hydration compare to ΔH solution in exothermic solutions

|ΔH hydration| < |ΔH solution|

Solubility

max amount of solute that dissolved in given amount of solvent at given temp

Insoluble

solid has little to no solubility

Soluble

solid has high solubility

Immiscible

liquid has little to no solubility

Miscible

liquid has high solubility

Unsaturated

< max amount of solute

Saturated

= max amount of solute

Supersaturated

(>) max amount of solute

What happens to the solubility of solids and liquids as temp increases

solubility increases

What happens to the solubility of gases as temp increases

solubility decreases

What happens to solubility as pressure increases

solubility increases

Concentration

amount of solute dissolved in a given amount of solvent