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37 Cards in this Set
- Front
- Back
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polarizability
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deals w/ london dispersion forces; ability to distort the e- cloud and create an instantaneous (temp.) dipole moment
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types of intermolecular forces
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ion-dipole
dipole-dipole london dispersion hydrogen bonds |
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ion-dipole
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partial charge of polar molecule and an ion
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how do you increase magnitude of ion-dipole bond?
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increase charge of the ion or magnitude of the dipole
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dipole-dipole
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between neutral polar molecules
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As molecular weight increases, polarizability....
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increases b/c electrons are further from the nucleus(positive)
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Shape affects bonds b/c....
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more areas to contact/bond create stronger forces.....
(a straight line has more space to contact than a compact ball) |
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in general....
if only dispersion forces --> if dipole --> |
look at molecular weight
look at polarity |
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as molecular weight increases, boiling point....
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increases (unless other bonding has an effect)
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surface tension
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energy req'd to increase the SA of a liquid by a unit amount
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how does capillary action work
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adhesive forces (tendency of molecules to stick to a surface) increase SA however the cohesive forces (tendency of molecules to stick together) want to decrease SA; so liquid rises until forces are in equilibrium
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vapor pressure
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external pressure on a liquid when amt of molecules going into gaseous state equals amt of molecules reentering the liquid
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q (amount of heat transferred)=
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Cs(specific heat) x mass x change in temp
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critical temperature
greater molecular forces, critical temperature.... |
lowest temperature that a gas can exist
increases |
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critical pressure
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pressure at the critical temperature
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volatile
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high vapor pressure substances that evaporate more quickly than substances with a lower vapor pressure
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as temperature incr, vapor pressure incr, and volatility....
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increases
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a liquid boils when its vapor pressure equals
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external pressure acting on the surface of the liquid
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as pressure incr, boiling point
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increases
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Why does the solid-liquid equilibrium line of H2O slant to the left?
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b/c its liquid state is more dense than its solid state as a result of its open arrangement
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2 types of solid structures:
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crystalline and amorphous
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cubic close packing
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ABC, ABC, ABC, ABC
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hexagonal close packing
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AB, AB, AB, AB
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what is the coordination number of both close packing structures
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12
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4 types of bonding in solids:
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molecular (atoms/molecules w/intermolecular forces)
covalent network (atoms connected in a network of covalent bonds) ex: SiO2, diamond, quartz Ionic (pos/neg ions) ex: salts metallic (atoms with metallic bonds) ex: Cu, Fe, Al |
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formula for volume of a circle
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volume= 4/3 pie r^3
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1 A =
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10 ^ -10 m
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the wt on the periodic chart is in amu. 1 amu = ??? g
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6.02 x 10^23 g
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Raoult's Law
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Partial Pressure by solvent vapor = mole fraction of solvent x vapor pressure of pure solvent
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as amount of nonvolatile solute in a solution increases, the vapor pressure ________ and the boiling point therefore need a _________ temperature to cause boiling.
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decreases
higher |
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how do you calculate the boiling point elevation?
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change in temp boiling = molal boiling point elevation constant x molality
then add this answer to the new boiling point |
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molality =
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moles solute/ kg solvent
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as molality increases
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the change in temperature also increases
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what does the molal-boiling-point-elevation constant depend on?
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the SOLVENT only. it doesn't matter what solute is present
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as the amount of solute increases in a soln, the freezing point _________ because the triple point is lower.
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decreases
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calculating the freezing point depression is the same as the boiling point elevation except ____________
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you subtract the answer from the typical freezing point instead of add.
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osmotic pressure
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= MRT
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