chapter 11 Flashcards
(29 cards)
what is the order of the 5 imfs in order of strongest to weakest?
- ion-ion
- ion-dipole
- dipole-dipole
- dipole-induced dipole
- induced dipole-induced dipole
how do you compare the strenghs of 2 ion ion forces?
-boiling point (Higher bp = stronger force.)
- charge of ions
how do you compare strenghs for ion dipole forces?
- higher charge = higher attraction
- bigger dipole moment = stronger attraction
- smaller radius = stronger ion
- biggest ΔH (absolute value) = stronger bond
what is an example of ion dipole forces?
dissolving nacl in water. By trading the only ion ion force for 6 forces. That’s why nacl dissolves well.
what does the dipole dipole force influence?
the evaporation of a liquid and the condensation of gas.
how to compare strenghs of dipole dipole forces?
- boiling point: higher bp = stronger force
- ΔHvap: bigger = more polar = stronger force
if oxygen is a central atom, is the molecule polar?
yes, because it creates a bent geometry.
why does water have the highest boiling point?
since water has many opportunities for Hbonding (2H and 2 lone pairs), thoses bonds are very strong and hard to destroy.
why does ice float on water?
in the liquid state, molecules of water move around. Though, when it freezes and becomes ice, the water molecules all arrange perfectly in a way that leaves a lot of empty space, so it’s less dense.
what is the name of the action of inducing a dipole?
polarization
how does the molar mass affect the solubility of a dipole-ID force?
the bigger the molar mass, the larger the electron cloud (so the higher the polarizability, the bigger the dipole moment, the higher the solubility.
how to compare strengths of dipole-ID forces?
- using molar mass or number of electrons.
what is the only possible force in two nonpolar molecules?
ID-ID
how to compare strengths of ID-ID?
- size (bigger molecule = bigger polarizability = stronger)
- ΔHvap: higher = stronger
- bp : higher = stronger
what is ΔHvap?
the energy needed to vaporize a molecule (enthalpy of vaporization)
what is the relationship between ΔHvap and bp for nonpolar liquids?
- bp/ΔHvap increases as the size increases
what are the exceptions to the relationship between ΔHvap and bp?
when there is a Hbond
what is the vapor pressure?
- the pressure exherted by the vapor in equilibrium with the liquid phase.
- a measure of the tendency of liquid molecules to escape from liquid phase and go into gas phase at given T.
what is the relationship between Pvap and bp?
higher bp = more polar = stronger = less volatile
what is viscosity?
the resistance of liquids to flow.
what is the relationship between size and viscosity?
bigger = more tangling = difficulty to flow = more viscous
what is the relationship between viscosity and imfs?
stronger bond = harder to flow = more viscous
what is surface tension?
the net inward force created at the top of a liquid which creates a tension at the surface.
how do you break surface tension?
- using mechanical energy
- adding something on top (ex soap)
