RSC Olympiad for Year 13 chemists

Here is the link to the Royal Society of Chemistry's olympiad website, as promised!

www.rsc.org/education/teachers/learnnet/olympiad_L6.htm

You will first need to register as a student. Please use my email address when prompted for your teacher's details. You can then download practice olympiad papers to give you an idea of what to expect in the real thing!

Have a really great summer..... and don't forget that piece of homework that's due in on the first day back in September!

Mass Spectrometry and Infrared Spectroscopy

Do we need to know *how* they work. I looked on syllabus and as far as I could tell we do not need to know how we get the graphs, just how to use them, but wanted to make sure . .

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?

. . . . .

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.