Pradyun Singh (Period 3, Semester 2)

Gases

IMF

Solutions

Kinetic Molecular Theory

Average kinetic energy is same at certain temperature

Gas particles are always in motion

No attraction between the gas molecules

The gas particles don't have volume

Collisions are elastic so no energy is lost

Ideal Gases

Seen at high temperature and low pressure

Imaginary Gases

Boyle's Law

Pressure is inversely related to volume

p1v1 = p2v2

Charles' Law

Volume is directly proportional to temperature

Gay Lussac's Law

Pressure directly proportional to temperatuer

Avogadro' Law

volume and moles are directly proprtional

Diffusion

Gases mixing

Heavier gases diffuse slower

Effusion

Gases escaping through a pinhole

Heavier gases effuse slower

Forces between two molecules

4 main types of IMF

London Dispersion Forces

Hydrogen Bonding

Dipole-Dipole

Ion-Dipole

Increase with increased molar mass as greater polarizabilty

Bond between hydrogen and F,O,N

Between 2 polar substances

Stronger than dipole-diple and London forces

All molecules have london forces

momentary induced dipoles

Determines state of molecules

Stronger IMF has increased boiling and melting point

Larger charge is a stronger attraction

Permanent

Phase Diagram

Triple point is where all 3 states are possible

temp constant during phase change

Boiling occurs when vapor pressure = atmospheric pressure

Homogeneous mixture

Solute dissolves in solvent

Solvent is medium which solute dissolved in

Numerous ways of expressing solutions

Molarity is moles of solute/ liter of solution

Molality is moles of solute / kg of solvent

Mole fraction is mol of solute/ mol of solute + solvent

mass solute/ mass solution * 100%

Energetics of Solutions

delta H of solutions = delta H of solute + delta H of solvent + delta H of mix

deltaH solute and delta H solvent are both endothermic as overcoming attractions

delta H mix is exothermic as new attractions

Like dissolves like

Factors favoring solutions forming

Exothermic, increase entropy

Vapor Pressure at surface of liquid

At equilibirum rate of condensation = rate of vaporization

Raoult's Law

A nonvolatile solute lowers vapor pressure of solvent

Psolution = Xsolvent * Psolvent

Both volatile

Ptotal = XaPa + XbPb

Ideal solution is when delta H = 0

Negative deviation is when lower than predicted

Solute, solvent is similar so strong attraction. Delta H solution is large and negative

Positive deviation is when higher than predicted. Solute and solvent are dissimilar

Solubility of solids increase with temperatuer

Solubility of gases decrease with increased temperature

Solubility of gases increase with increased pressure