CHM 103: EXAM 4

b/t ions & polar compounds VERY STRONG

'super' dipole-dipole molecules containing H bonded with F, O, or N

b/t all molecules and atoms due to temporary dipoles increase with increasing molecular/atomic polarizability Polarizability increases with mass (# of e) when molecules have similar mass, consider how shape impacts interaction

the resistance of a liquid to flow greater in substances with stronger IM forces increasing in longer molecules that can interact over a greater area and possibly become entangled

the phase transition from liquid to gas increases with inc T and inc Surface area decreases with increasing strength of IM forces

pressure of a gas in dynamic equilibrium with a liquid normal boiling point- T where the vapor pressure of a gas equals 1 atm Boiling point- T where vapor pressure of a gas equals the external pressure water boils at a lower T at high elevation because atm is lower

units- atm, Pa, mm Hg, torr open end manometer: Pgas= Patm + delta h

P1V1=P2V2 (constant T and n)

V1/T1=P2/T2 (constant P and n)

V1/n1=V2/n2 (constant P and T)

P1V1/T1= P2V2/T2

PV=nRT STP= 1 atm, 0C Molar volume: 1 mole of an ideal gas @STP= 22.4L Density of a gas: d=P*mm/RT (mm=molar mass) determine molar mass of a gas given info on a sample mass, T, P and V

Ptot=PA+PB+PC... (dalton's Law of Partial Pressures) PA= nART/V, PB=nBRT/V, PC= nCRT/V

XA = nA/ntot PA = XA*Ptot

Pgas = Ptot -- PH20

write a balanced chemical reaction involving gases (PVT of gas A ==> amount A (in moles) ==> amount B (in moles) ==> PVT of gas B)

Postulates gases molecules/atoms are in constant, straight line motion V of gas particles in negligible compared to volume of container IM forces b/t gas particles are negligible collisions b/t particles and container walls are completely elastic Avg KE of particles is proportional to the Tin Kelvin Real gases do not adhere to #2 at high P and #3 at low T

@ a given T, lighter particles travel faster (on avg) than heavier particles As T inc, the velocity destribution of gas molecules shifts towards higher Ts and becomes less sharply peaked for a gas sample: KEavg= 3/2 RT

Repulsion of e groups determines molecular shape Electron grps: single bonds, multiple bonds (double, triple), lone pairs of e, single lone e

linear- 180 degrees trigonal planar- 120 degrees tetrahedral- 109.5 degrees

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excel graph

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dipoles are vector quantities estimate net dipole to determine molecular polarity

covalent bond rep'd by overlapping atomic orbitals overlapping orbital may b standard atomic orbitals ( i.e. s, p) or hybridized atomic orbitals (i.e. sp, sp2, sp3) hybrid orbitals the # formed is = to # of atomic orbitals mixed E is intermediate b/t those of the mixed atomic orbitals molec geo det by geo of overlapping orbitals same shapes as VSEPR sigma bond-single bond b/t 2 atoms involving hybridized orbitals Pi bond-sidebyside overlap of unhybrid p orbitals with overlap above n below sigma bond axis