Chemistry 12 week

Ion-dipole

between ion and polar molecule; increases with magnitude of dipole moment, magnitude of ionic charge and decreasing separation

Bond order

# bonds= 1/2(#electrons in bonding MO-# of electrons in antibonding MOs)

Which of the compounds listed below are capable of forming hydrogen bonds between their molecules?

(CH3)2NH, HF, HOCH2CH2OH

lowest to highest change in energy

(lowest)Metal, semiconductor, insulator(higher)

intrinsic semiconductor

conducts electricity, but not as well as a typical metal

gas to solid

deposition

Potential

energy by virtue of its position relative to a force Ex. Gravity

Endothermic

energy enters system Absorbs heat Ex. Bond breaking melting sublimation

Exothermic

energy leaves system Releases heat Ex. Bond making Wax hardening Dew Formation Na+ + Cl- ---->NaCl

Kinetic

energy of motion

Surface Tension

energy you have to put in to deform the surface of a liquid

Hydrogen bonds

especially strong type of dipole-dipole; occurs between molecules with H and N,O,F

liquid to solid

freezing

energy flows from

high temp to low temp

Anti bonding Molecular orbitals

higher energy, so less stable tan separated atoms

entropy

how much you spread energy out

electrolyte

is a solute that has mobile ions carry current

solution

is homogeneous mixture ex. air, salt water

"p" and "n" indicate

junction

IMF=KE

liquid

Bonding Molecular orbitals

lower energy; so more stable than separated atoms

work

manifestation of energy transfer due to a mechanical process directed energy (directed energy) w= F x D

heat (q)

manifestation of energy transfer due to a temperature differnce non-directed, random energy

solid to liquid

melting

molarity

moles of solute/liters of solution

n-type

negative particle (electron)

Dipole-dipole forces

occur between polar molecules; increases with strength of dipole

London Dispersion forces

occurs between all molecules; depends on mass, size and polarity

System

part of the universe that you are interested in

p-type

positive charge carrier

state function

property of a system just by virtue of position wherever its in

path function

property of a system which depends on how you do it

thermal equilibrium

situation that results spontaneously sometime after two objects at different temperatures are brought into contact

IMF>KE

solid

ionic compounds (metal + nonmetal)

strong electrolyte

Arrange the ionic compounds CaO, BaCl2, and Na2O in order of decreasing strength of the attraction between their ions.

strong-CaO,Na2O,BaCl2-weak

Thermodynamics

study of energy and its transformations

solid to gas

sublimation

Acids

tart taste turn blue paper red

Viscosity

the ability of molecules to flow -Viscosity decreases, IMF decreases

Energy

the capacity to do work

Which of the following best describes the term molar heat of vaporization?

the heat required to convert 1 mole of a liquid substance at its boiling point to the vapor state

Which of the following best describes the term molar heat of fusion?

the heat required to convert 1 mole of a solid substance at its melting point into the liquid state

Surroundings

the rest of everything else in the universe

Universe

the sum of system and surroundings

boiling point

the temperature at which a liquid and gas phase are in equilibrium

Bases

turn paper blue slippery

most molecular covalent compounds are

weak or electrolytes Ex. Sucrose, Ethanol

energy transfer continues until

you reach thermal equilibrium

CH3CH2CH3 lewis structure

-Polarity:Nonpolar -London: Yes -Dipole-Dipole:No -Hydrogren Bonds: No

CH3COCH3 (Acetone)

-Polarity:Polar -London: Yes -Dipole-Dipole:Yes -Hydrogen Bonds: No

CH3CHOHCH3 lewis structure

-Polarity:Polar -London: Yes -Dipole-Dipole:Yes -Hydrogen Bonds: Yes

Glycerol

-Polarity:Polar -London: Yes -Dipole-Dipole:Yes -Hydrogen Bonds: Yes

Propanoic acid

-Polarity:Polar -London: Yes -Dipole-Dipole:Yes -Hydrogen Bonds: Yes

Cost energy

-breaking up solvent-solvent interactions -breaking up solute-solute interactions

Which of the following phase transitions are exothermic?

-freezing -deposition -condensation

Which of the following phase transitions are endothermic?

-melting -evaporation -sublimation

CH3COOH (acetic acid) can form hydrogen bonds between its molecules. Based on the Lewis structure shown below, how many hydrogen bond donor and acceptor atoms does this molecule have?

1 H-bond donor atom; 4 H-bond acceptor sites

When an object is heated, the quantity of energy transferred depends on

1)substance 2)Mass of Substance 3)change in temp

extrinsic semiconductor

A doped semiconductor

first law of thermodynamics (law of conservation of energy)

DeltaEuniv = DeltaEsys + DeltaEsurr= 0

Why do the strengths of London (dispersion) forces generally increase with increasing molecular size?

Dispersion forces arise from dipoles caused by the electron distribution being distorted. Larger molecules have more electrons and, therefore, more distortions and a bigger force.

IMF<<KE

GAs

Strong Acids

HCl HBr HI HNO3 HCLO4 H2SO4

If the reaction is endothermic, what happens to the internal energy of the system when the reaction is proceeding?

It increases.

most common strong bases

Metal OH

Dilutions

Molarity1 x Volume1 = Molarity2 x Volume2

Which, if any, of the following nitrogen oxides have the same empirical formula?

N2O4, NO2

most common weak base

NH3

Which of the following compounds could form a hydrogen bond with another molecule of the same compound?

NH3, Ch3OH

What causes the high viscosity of molasses?

The intermolecular forces between the molecules of molasses (hydrogen, dipole-dipole and dispersion) are substantial because the molecules are large and the interactions between the molecules are strong.

Equlibirum

a dynamic condition described by equal rates for opposite processes

Titrations

acid + base ---> water + salt

soluble ionic compounds and acids are

all electrolytes

specific heat

amount of heat energy you have to add to a substance to change its temp of 1 gram ofmaterial by 1 degree -Units: J/g degree Celsius

Hydrogen bonding is an attractive force that plays a key role in determining the physical properties of molecular substances. What features are required for a substance to experience hydrogen bonding among its own molecules?

an O, N, or F atom with one or more lone pairs H bonded covalently to O, N, or F

Weak Acid

any other acid

Why are hydrogen bonds considered a special class of dipole-dipole interactions?

These interactions are with polar molecules but are stronger than dipole-dipole interactions. These interactions account for the higher melting and boiling points observed for certain molecules such as water.

System + Surroundings=

Universe