What is evaporation?

If volatily is the ease with which a liquid turns into a gas, then does that mean all liquids evaporate? Is evaporation the state change from liquid to gas? Does this happen at below the boiling point (eg leaving some water at room temperature) because of the Boltzmann distribution, i.e. even at a temperature of 20 degrees celsius, some molecules have enough energy to turn into a gas, and eventually all molecules will leave the container in which the liquid is held?
Is it only liquids that do this (can sublimation be spontaneous, without a heat source?), and is there any point below which liquids do not evaporate, except melting point? Or does it just become so slow near the melting point that it can not be observed?
Also, when you're boiling a kettle, some of the water is turning into steam (a gas) which you can't see, immediately next to the spout, but what you can see is water vapour, a little further away from the spout, where the steam has hit the (relatively) cold air and condensed into water droplets, liquid suspended in air. Is this correct?

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When drawing mechanisms for reactions is it necessary to show lone pairs of electron like in the book on page 158.
Also, do we need to know how to use bond enthalpies for substances that are not gases yet?

Carbon double bond

In a carbon double bond is there two pi bonds, one above the sigma bond and one below.
Or
Is that one pi bond.

Halides dissolving in polar solvents

A simple molecules structure e.g. Cl2, does not dissolve into polar solvents but does dissolve into non-polar solvents, but when it becomes an ion, e.g. Cl-, can it then dissolve into polar solvents but not non-polar solvents?

Non polar molecules with polar bonds

CCl4 is a non polar molecule with polar bonds because the dipoles acting in different directions cancell each other out . . .
I was wondering whether if one of the Cl atoms was replaced with another atom, say fluorine, would it still be a non polar molecules because the resulting dipole means fluorine is still slightly negative, or will it now be polar.
Im thinking it is polar because they the charges a no longer equal, so it is no longer electronically symmetrical, but I wanted to check.

Lone pairs

Just read that the reason they have more repulsive force is because whilst the bonded pairs are attracted to two nucleus's, they are attracted only to the central atom. This means it repel bonded pairs more as it is more concentrated around the central atom.
This right?

SO2

Several times when doing a dot and cross diagram I have done it differently to the actual answer, ever though I swear mine makes more sense.
Using the octet rule, even though I know there is the expansion of the octet, it wants to have a full shell (even though I realise 8 electrons is not a full shel for the sulfur) and be stable etc.
So I put in a dative covalent bond between on oxygen atom; and then a double covalent bond between the other oxygen atom and the sulfur atom.
This means all the atoms have stable shells, so why does it instead form two double covalent bonds? Is 8 not a very stable number when it is to do with the third shell? Does the oxygen form a double covalent bond because less energy is required to do that than the sulfur to form a dative covalent bond?

Also, the final shape of this is non-linear and 120 degrees. In this case then does the lone pair have the same repulsion power of the two covalent bonds?
All this came up for me in the question 3 c) on page 59.

Titration question

100cm3 of IO3- (aq) has a concentration of 0.023 mol/dm3
Calculate the maximumn mass of iodine which could be obtained from this solution.
Assume all IO3- can be converted to I2.

When it says, assume all can be converted to I2, does it mean I can assume the number of moles of IO3- is the number of moles of I2 I can get?