Stephie Garcia Egg in the Bottle Air inside expanded egg traps that air in there Air inside cools decreases pressure in the bottle Air molecules inside and outside are pushing on the egg Pressure on the inside is lower than the outside so egg is pushed into bottle Gravity is not involved in pulling egg into the bottle o Proof tried it upside down Need higher pressure outside bottle than inside o Blow air into bottle o Heat bottle up Chapter 12 Intermolecular Forces and Liquids Ideal Gases Last semester treated all gases as ideal gases Assumptions Characteristics o No intermolecular forces molecules are so far apart there s no interactions o Gas molecules had no volume not true o Elastic collisions with other molecules no loss of energy 22 4 L gas vs 18 mL liquid water Most all gases behave as ideal gases in standard situations o Exceptions extreme situation Gases Liquid Solids What s changing as a gas condenses into a liquid and then freezes into a solid Gas Liquid Solid Fill container Fixed volume Fixed volume Assume shape of bottle Assumed shape of bottle Fixed shape Vibrational Vibrational Rotational very small Translational Translational Vibrational Rotational Rotational Glass is thicker at the bottom than it is at the top o When glass is flattened out the edges are thick o Panes are cut and installed thick side down o Glass is a solid not a liquid no translational movement Solid not enough energy to overcome intermolecular forces Liquid more energy through heat to overcome intermolecular forces Gas even more energy to overcome intermolecular forces enough to get so far away that the forces have no more effect on molecules Stronger intermolecular forces something will melt at a higher temperature Volume Shape Motion Clicker Intermolecular attractions are electrostatic in nature The magnitude strength of these interactions is dependent on A The amount of charge on the particles B The mass of the particles C The size of the particles D The density of the particles E The kinetic energy of the particles Strength is dependent on the amount of charge product of that charge Size is a factor as well because the smaller the ion is the closer the ions can get to each other Density and kinetic energy are not factors on the strength o Increased energy does not affect the strength of intermolecular forces o Increased energy only helps to overcome the intermolecular forces The larger the atom is the easier it is to lose track of electrons The smaller the atom is the harder it is to lose track of electrons Mass doesn t affect strength only size is important Intermolecular Forces Ions have full charges polar molecules have a dipole positive negative end nonpolar molecules no charge Ion Ion CH 13 o Easy to see o Positive with negative o Obviously stronger than dipole dipole Ion Dipole Dipole Dipole o Molecule that is polar o One side is negative other is positive o Partial charges vs ion s full charges Hydrogen Bonds o Special case of dipole dipole o H attached to very electronegative element o H bond with another electronegative element on a neighboring molecule o Water partial negative on oxygen partial positive on hydrogen Hydrogen bond between O H o Stronger than dipole dipole interactions Dipole Induced Dipole Induced Dipole Induced Dipole o London forces induced dipole temporary o Ex large atom with large electron cloud Nucleus moves faster than the electron cloud can adjust Nucleus is closer to one side of the atom than the other for a moment For that moment there is a dipole o o Even weaker than a dipole dipole Everything exhibits these London forces b c everything can be deformed out of it s normal state Ions polar molecules etc Clicker Which of the following compounds would be expected to form intermolecular hydrogen bonds in the liquid state A CH3OCH3 B CH4 C HF D CH3CO2H E Br2 F CH3OH Dimethyl ether polar H has to be bound to O F or N very electronegative elements HF H is bound to F can bind to a neighboring F CH3CO2H H is connected to an O Br2 no H is even present CH3OH looks like water not as strong but still has an H bond Clicker Rank the following atoms or molecules in order of increasing strength of intermolecular forces in the purse substance A CO2 B NH3 C CHCl3 D CCl4 CO2 Induced dipole NH3 Hydrogen bonding CHCl3 polar dipole dipole CCl4 induced dipole Induced dipole depends on size polarize ability of molecules o CCl4 is larger than CO2 o So it will be stronger ADCB