Chapter 11 Flashcards
How do the densities of gas liquids and solids compare?
Gas has the least density
Then solid then liquid
How does the volume of a gas liquid and solid compare?
Gas has most volume then solid and then liquid
What are the two ways states of matter can be changed?
Changing the temperature and/or the pressure
What are London dispersion forces?
The result in changes of electron distribution (since all atoms have electrons they all exhibit dispersion forces)
How can we determine the magnitude of dispersion forces?
Using molar mass- higher molar mass= higher boiling point= greater forces
Using shape of molecule too
What is a dipole-dipole Force?
Exists in all molecules that are polar
How do the boiling points of polar molecules compare to non polar molecules of similar mass?
Polar molecules have higher boiling points since they have dipole dipole forces
What is miscibility?
The ability to mix without separating into two phases
Polar molecules are miscible with other polar molecules but not non polar ones
What is hydrogen bonding?
They are polar molecules containing hydrogen atoms bonded directly to small electronegative atoms
(Sort of super dipole-dipole bond)
H-F
H-O
H-N
What’s the difference between intermolecular and intramolecular?
Inter- between molecules H-F
Intra- chemical bonds within molecules
What is an ion dipole Force?
Occurs when an ionic compound is mixed with a polar compound
NaCl + H2O
What are the strengths of the following bonds in order of least strongest to strongest? Ion-dipole Hydrogen bonding London dispersion forces Dipole-dipole
Weakest Dispersion Dipole-dipole Hydrogen bonding Ion-dipole Strongest
What is surface tension? How is it affected by intermolecular forces?
The energy required to increase the surface area by a unit amount
Decreases with decreasing intermolecular forces
What is viscosity? How is it affected by intermolecular forces?
The resistance of a liquid to flow
It is greater in substances with stronger intermolecular forces
What is vaporization? Exothermic or endothermic?
Going from liquid to gas
Endothermic
What is condensation? Exothermic or endothermic?
Gas to liquid
Exothermic
What does volatile mean?
Liquids that vapourize easily are volatile
What is the heat of vaporization? What’s the sign for condensation?
What’s the sign for vaporization?
The amount of heat required to vaporize one mole of a liquid to gas
ΔHvap
Condensation is negative sine it’s exothermic
Vaporization is positive since it’s endothermic
How does water act in a sealed container?
Dynamic equilibrium occurs where the rate of evaporation is equal to the rate of condensation
What is the vapour pressure of a liquid? How do intermolecular forces affect this?
The pressure of a gas in dynamic equilibrium with its liquid
Weak intermolecular forces= higher vapor pressure
What is he boiling point of a liquid?
The temperature at which it’s vapor pressure equals the external pressure
What is the normal boiling point of a liquid?
The temperature at which it’s vapor pressure equals 1 atm
What is sublimation?
Going from solid to gas
What is deposition?
Gas to solid
What is fusion? What is the heat of fusion? Endothermic or exothermic?
Melting (solid to liquid)
ΔHfus= the amount of heat required to melt 1 mol of a solid
Positive since it’s endothermic
What is the triple point?
Represents the unique conditions at which three states are equally stable and in equilibrium (all three states at once)
What is the critical point?
Represents the temperature and pressure above which a supercritical fluid exists
