imf and gas

electronegativity

tendency of an atom/group to attract electrons

0.4 < ∆e < 1.7 = polar

non polar if arrows pull equally in OPP directions

ion forces

1. higher charge

2. smaller atomic size

   = stronger forces

ions are RAW charges

ion-ion

b/w IONIC bonds

1. charge

2. size

STRONGEST imf

ion-dipole forces

b/w polar molec & ions

1. ion’s charge

2. polarity of molec

energy of solvation (energy to dissolve smt) INCREASES by stronger ion-dipole force

• size decrease, charge increases

energy of solvation

energy to dissolve a solute in a solvent

INCREASES by stronger IMF

energy of hydration is one type

(ONLY ION-DIPOLE) charge > size

• ion in water

soluble if

polar solvent

(water is polar) form H bonds - has OH, COOH, NH2

ionic/polar

NOT long alkanes

np solvents can dissolve np

dipole-dipole forces

b/w polar molecules

1. polarity of molecule (EN)

   ∴ high dipole moment → high dipole-dipole

stronger the imf

harder to overcome bonds

• higher boiling/melting points

polar > nonpolar

polars have permanent dipoles

np are temporary

hydrogen bonding

STRONGEST form of dipole forces

part of dipole-dipole

hydrogen atoms like to have F.O.N

they prefer to bond to very EN atoms

dipole-induced dipole

b/w polar and non polar

TEMPORARY attraction

the amount of inducibility → polarizability

• “how easy to shift/shape the non polar”

dipole forces

polarizability

since its temporary, based on how many electron clouds

more e clouds, more electrons that can shift into a shape

think pixels

induced dipole induced dipole

(london dispersion forces)

affects all molecules, but VERY temporary and weak

occurs when electrons bunch up on one end causing a temporary dipole

np+np only has london force

isomers

straight chain will be bigger cuz bigger surface area

branches are itty bitty

vapour/gas pressure

weaker force = molecules escape easily = higher gas pressure

stronger force = molecules held tighter = lower gas pressure

gas molecules

gases exert pressure off its container

constant rapid motion ∴ low IMF

NO attraction

ALWAYS CONVERT CELCIUS TO KELVIN

phase changes

imf breaks when heats (endothermic)

cuz particles part away

imf forms when cools (exothermic)

particles need a force to squeeze them tgt

gases characteristics

• invisible irl

• very spaced out fills shape and vol

• low density

• elastic collisions (dont stick and flowy)

standard temp and pressure (STP)

measured in sea level

temp: 273 kelvin, 0°C

pressure: 1 atm, 760 mm Hg, 760 torr, 101.325 kPa

boyle’s law

pressure is inversely proportional to volume

• pressure increase, volume decreases

P1 x V1 = P2 x V2

to boil on stove u “press(ure) the volume”

charles’ law

volume is proportional to temp

• when temp increases, vol increases

TEMP IN KELVIN

V1/T1 = V2/T2

gay lussac’s law

pressure is proportional to temp

• temp increases, pressure increases

P1/T1 = P2/T2

Avogadro’s law

volume is proportional to # of moles

• vol increase, moles increase

V1/n1 = V2/n2

combined gas law

• # of moles is constant

• temp in kelvin

• stp is 273, 1 atm, 760 mmHg

ideal gas law

used to calculate gases in ideal conditions

PV=nRT

R = GAS CONSTANT 8.314kPa(L/mol)(K)

dalton’s laws of partial pressure 1

law 1 - the sum of the partial pressures = total pressure

P1 + P2 = P total

daltons law 2

the sum of partial moles = total moles

n1 + n2 = n total

daltons law 3

partial pressure:total pressure = partial moles: total moles (mole fraction)

P1/P total = n1/n total

graham’s law

R1²/R2² = M2/M1

use to find unknown molar mass

the rate of flow of gases depend on the molar mass of the gas

lighter=faster, heavier=slower

diffusion

mixing of different gases by random molecular collision and motion

effusion

gas molecules escape through a small hole of its container without any collision