This Week In Chem....(Lame Title Right?)

So this week in Chemistry was a bit of a refresher course in the history of the atom. I know, you're jealous right? Actually I remember that at some point in Intro to Chem I had learned all of key points (Rutherford's Model, Cathode Ray Tubes, Plum Pudding Model, etc...) but promptly forgot it all after the chapter test. The most important points that we cover this week include, the progression of models of the atom (Democritus, Dalton's Atomic Theory, Thomson's Plum Pudding Model, Rutherford's Atomic Model, and Chadwick's revised Atomic Model with the neutron. We also learned how they discovered the sub-atomic particles (Cathode Ray+ Magnet (Electron), the Gold Foil experiments (Protons), Chadwick's discovery (Neutron). The last bit of learning that went on this week involved Atomic Number (# of protons or electrons in an element, what makes and element that element) and Atomic Mass (# of Protons+ # of Neutrons, usually both #'s are equal unless it is an isotope(Element with extra neutrons)). So this all basically sums up the week in Chem, minus the completely off topic discussions that came up during homework time on thursday. I should've probably been doing more homework and less talking but, hey it all worked out...

Separation Techniques Lab

So this last week in Chem we have been doing a Lab on separation techniques... And now that the lab is over we are supposed to write a blog post on what we learned. The first technique that we worked with was filtration. Filtration works by running the mixture through some kind of screen or filter to separate mixtures, like sand from water. Another experiment that was done was separating iron fillings from sand, this was accomplished by using a magnet to pick out all of the fillings.

The experiment that worked I on was Distillation. The way that the experiment worked was that we took a mixture with 5.25g of sugar dissolved in 100ml of water and put it into a distillation apparatus.  The way that the apparatus worked was the water was in a flask on top of a heating element with a rubber stopper and plastic tube in the top of it that connected to another flask sitting 9 inches away on the table. (look at the picture if you don't get it) The water evaporates from flask 1 and the vapor travels through the tube (which was cooled by wet paper towels), condenses and drips down into flask 2. Once the water has all evaporated you are left with a mass of gooey sugar in the bottom flask 1. Once the water is all gone then you should take the sugar off of the heat otherwise you will end up getting a permanent layer of burnt sugar        in the bottom of your flask....which is no fun to clean off. Trust Me.

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Distillation Apparatus

The last lab that we did was a chromatography lab. Chromatography works by having a solvent (water) dissolve ink that is on some kind of a matrix (filter paper). The lighter particles in the the ink are carried farther through the matrix by the water. The heavier particles stay farther back near the original line drawn on the matrix. After the water has traveled through the paper and the ink has separated there is a pretty cool pattern left on the matrix.

Chromatography!