Lab experiment- sepation techniques.

In this lab experiment, we learnt about separation techniques and its applciations in our daily lives. Adding on the Chromatography experiment, we did evaporation to dryness . Evaporation to dryness is an interesting process. As its name suggests, a solution is evaporated to dryness to get the soluble solute from the solution. For example a salt water is evaporated completely, and its residue would be salt a perhaps a little impurity. I find this process interesting as it is closely linked to Crystallisation which evaporates almost all the solvent till a bit is left. The solution is then left to cool down. Next because there is a small quantity of solvent, satuation point of the solute is reached and thus when the solution is filter, crystals is the residue. Crystallisation can be used to get sugar sucrose from sugar beets. This is a video of evaporation to dryness, enjoy

Separation Techniques

After the group work, later on in term 3, we learnt more about separation techniques. We learnt that there were several separation techniques such as filtration, evaporation to dryness, distillation, magnetic attraction, crystallisation, and chromatography.

It is interesting to find out that different techniques have different applications, they also have different apparutus in the separation process. For instance, crystallisation is used fir production of silcon cafers for microchips, and also production of sucrose sugar from sugar beets. Those sweet delicacies which we enjoy also goes through a separation process before we can eat them.

Next is the chromatography process. Chromatography is the simple process to test for a substances in a dye, etc. I did the simpler process of chromatography which involves using a chromatography paper with a dye, soaked in a solvent, preferably alchohol. The substances in the dye then separates as they have different solubilities. What I like about chromatography is that this simple yet useful application has been helpful to the society as it is used to test for banned substances too. For example, police use urine samples for chromatography so that they can find out if the suspect is taking drugs.

http://http//www.youtube.com/watch?v=9Oy98D6if1c

Separation Techniques Group work

Separation techniques was a topic which was onlly briefly covered at first. That was during the beginning of the june holidays. We were split into groups, our objectives was to use the given apparatus and solve a problem stated on an e-learning site.
Back then, we knew little about separation techniques, but still, my group fared much worse than other groups as we only got 1 ace points. When I reflect back on our work and compare that to group 2 from my class. I realised why our work was really insufficient. You can go to science excite, the blogpost on Home Learning PBL to find out why.
I will just brief you why now. My groups work is bacsically not clearly stated, it lacks reasoning and explanations, also the theory and keywords used were wrong. While on the other hand, 1a2 groups 2's work did a brilliant work because,

1)They first pointed out the main aim and the problem to be solved of the experiment
2) Apparatus available
3) Step by step procedure, including pictures and diagrams, most importantly was their explanation for every point they have said and also, their organisation makes it easier for the reader to read the work.
One example would be that they first distinguished the different properties of the substances present in the poluted sea water.

Miscible or immiscible: 1)oil, 2)alchohol( liquids)
3) Sand and gravel (Solid)
4) Broken glass bits (Solid)
5) Remnants from dead organisms (Solid)

They also stated the apparatus needed such as separating funnel, and fractional distillation. This will give the reader a better idea of how the sea water is separated from the inpurities, together with the visual aid of the diagrams and pictures.

The bigger scale project cannot be successful as the cost is high and not all inpurities will be removed. This can thus be related to my ACE project in my earlier post about NEWater. The NEWater process includes using reverse osmosis, micro-filtration and uv disinfection. You can find out more about my ACE project in my earlier post.

Elements, Compounds and Mixtures

Elements is the simplest kind of matter and there are over 100 of them. Elements are grouped in a periodic table which consists of periods and groups. Elements in the same period are lined up according to their atomic number on the bottom left-hand corner, while the atomic mass is on the top. Periods are horizontal. Elements in the same group share similar chemical properties, and are vertical. Each element has an special symbol. Fron the left to the right of each period, the elements on the left are metal, and non-metal are on the right. Metals and non-matals have different properties, for example, iron and carbon. Iron is ductile and has high density while carbon is brittle and has low density.
Elements also have different uses. Aluminium is used to make foils and drink cans while, Chlorine is used to make bleach.
A compound consists of 2 or more elements chemically combined together. A mixture consists of 2 or more substances which are not joined together chemically, and it can be made up of elements , compunds or both. Elements in a compound are have different ratios, like 2:1, and compounds have a chemical formula. metallic elements always have their names come first in the compound's name. Mixtures have no chemical formula no given ratio. Compounds can be separated chemically by releasing energy. Mixtures can be separated by physical force.
Something interesting I did in the lab was to burn a magnesium with a bunsen burner. Miss leong asked gave everyone a small magnesium plate. We then use a pair of tongs to burn it in the flame. After burning the magnesium, it lit up into bright white light. The originally grey magnesium turned white after cooling it. This proves that elements are chemically combined and the release ofenergy as light was produced and the magnesium combined with oxygen to become magnesium oxide.


Here is a video I have found, enjoy :D