CHM 113 Chem Notes ASU 4 Exam 4

All things for EXAM 4 , Incomplete as of now, adding more lecture by lecture

IMF Forces and Phase diagrams: Unit 10

[Intramolecular forces]

  • strong attractive forces that occur between atoms within a molecule, primarily responsible for holding the molecule together. These forces include covalent bonds, ionic bonds, and metallic bonds, which vary in strength and result in different properties of compounds.

[intermolecular forces]

  • weaker attractive forces between neighboring molecules

[Types of IMF]

  • Ion-Dipole Forces: The strongest intermolecular force, existing between a fully charged ion (cation or anion) and a polar molecule (dipole), such as in a salt solution.

  • Hydrogen Bonding: A strong, special type of dipole-dipole interaction occurring when hydrogen is directly bonded to highly electronegative atoms like nitrogen, oxygen, or fluorine.

  • Dipole-Dipole Interactions: Attractive forces between the positive end of one polar molecule and the negative end of another.

  • Ion-Induced Dipole/Dipole-Induced Dipole: These occur when an ion or a polar molecule induces a temporary charge separation (dipole) in a non-polar molecule, disturbing its electron cloud.

  • London Dispersion Forces (LDF): The weakest and universal force present in all molecules (polar or non-polar). They arise from temporary, instantaneous dipoles caused by electron movement.

  • Strength Order (Strongest to Weakest): (strongest) Ion-dipole > Hydrogen bonding > Dipole-dipole > London dispersion (weakest).

  • Polarity: Only polar molecules exhibit dipole-dipole and hydrogen bonding, whereas non-polar molecules rely solely on London dispersion forces.

  • Molecular Weight: Larger, heavier molecules generally have stronger London dispersion forces.

  • In H2O2 the dipole moment comes from the O-H bonds

  • In C2H6o The dipole moment comes from O-C bonds

  • The difference of EN between O and h > between O and C

  • H is very small and close to O in H2O , so more e- density can be pulled away, This means: polarity of the O-H bonds > polarity of O-C bonds, H2O has stronger DDI’s than C2H6O, this is because H2O is a hydrogen bond

Due to Hexagonal shapes:

  1. Water is one of the few substances that expands upon freezing, which is due to the unique hydrogen bonding arrangement that occurs between water molecules as they solidify. Ice cubes float as solid is less dense than liquid water.

  2. Water bottles and sodas can explode in the freezer.

  3. Outside water (pipes) can burst in winter

  4. snowflakes have hexagonal shapes

[Jim experiment]

  • small little flask 3 total,

  • 50ml of water w food coloring in each, then poured into one flask together to make 100ml,

  • another flask of 50 ml of alch, added alch to water of 50 to make 100ml maybe? density diff

  • In another experiment: he has a big tube with 4 liquid, mercury, carbon hepta or like hecta chloride, mineral oil, and something else, all unmixed and shows 4 different layer, if mixed the 2 polar mix and 2 non polar would mix leaving 2 layers, but he does not mix.

  • he also has this other glass tube thing with liquid with a small tube in it and connected to an seemingly empty glass circle on top of it enclosed, pounded on it and the top circle became w pink liquid like a failed pink titration color

  • soap and water cant take off colored crayon stain written on surface due to polarity, wd40 takes it right off, like devolves like

  • immiscible vs miscible

  • big glass beaker, then small beaker with liquid water, big bucket of liquid nitrogen poured in big beaker, water has stronger imf than n2, combined them and a big explosion of vapor

  • water in wine glass poured to the brim and the water is actually past the top of the glass without flooding over—surface tension and viscosity that the imf stick together and not spill over

  • acetone in glass tub with paperclip on acetone and it sinks, glass tub w water and witj paper clip and floats then added soap and it drops

  • plastic tubleware of oobleck, under stress its solid and not under stress its like slime

  • ice skate on ice and how it works. The blade of an ice skate applies pressure to the ice, causing a thin layer of water to form due to the melting point depression, which reduces friction and allows for smoother gliding across the surface.

ADD : ENERGETICS AND THE STEPS , LATTICE, add extra stuff and then also put into a cleaner format

  • Lattice Energy: The stronger the London Dispersion Forces (LDF), the higher the lattice energy, making it more difficult for solvents like water to effectively break these interactions. Non-polar solvents such as WD-40, which are more compatible with the crayon, can penetrate and dissolve the wax effectively.

Hydrogen bonding is the strongest then check for dipole dipole and ldf

if same masses, then the polar one with dipole dipole is stronger

if very different masses, then dipole dipole doesn’t matter, LDF is more important even if one is polar.

Gas has very weak imf

liquid is second weakest

solid is strongest

Higher temperature has higher speeds thus more average KE

lower temperature has lower speed thus less average KE

critical temperature: TC is at which a substance can no longer exist as a liquid, regardless of the pressure applied, the highest T at which a liquid phase can exist

critical pressure: PC is the pressure required to liquefy a gas at its critical temperature, marking the transition from gas to liquid regardless of the temperature. Pressure required to liquify a gas at TC

weaker imf= lower critical temp and pressure

unit 11 gas:

P,V,T, and n

pressure: force per unit area exerted on a surface (torr, psi, ps, barr)

volume = amount of space occupied, L, ml, , cm3

temperature: a measure of the average kinetic energy of particles in a substance, expressed in degrees Celsius (°C), Kelvin (K), or Fahrenheit (°F).

standard temperature and pressure:

  • Standard Temperature and Pressure (STP): A reference point for gas measurements defined as 0°C (273.15 K) and 1 atm (101.3 kPa) of pressure, commonly used in scientific calculations.

quantity: H of has particles in moles.

boyles law: Boyle's Law states that the pressure of a gas is inversely proportional to its volume when the temperature is held constant, mathematically expressed as P1V1 = P2V2

charles law: Charles's Law states that the volume of a gas is directly proportional to its absolute temperature when pressure is held constant, mathematically expressed as ( \frac{V1}{T1} = \frac{V2}{T2} ).

avogadros law: Avogadro's Law states that the volume of a gas is directly proportional to the number of moles of gas when pressure and temperature are held constant, mathematically expressed as ( V \propto n ) or ( \frac{V1}{n1} = \frac{V2}{n2} ).

ideal gas laws assumes to have particles w zero volume, no attraction between particles,

at low pressure: particles size is negligible compared to size of container

at high temperature: particle has faster speeds, more energy to overcome intermolecular forces, allowing the gas to behave more ideally as the collisions become more frequent and elastic. (closer to having no attraction)

vander waals equation: P= nRT/(v-nb) minus n? a/(v2)

  • This equation accounts for the real behavior of gases by incorporating the volume occupied by the gas particles (represented by the term nb) and the attractive forces between them (represented by the term n^2 a / v^2).