Tuesday, May 31, 2011

Pre - Research ( Brendon Goh )

This project is to extract caffeine from drinks. So these are important things to take note:

Acidic: something with pH value of less than 7. 1 or 2 is considered strong.

Alkaline:Something with pH value of more than 7. 13 or 4 is strong.

solubility : It is the ability of a substance to dissolve in a liquid, for example, salt dissolving in water to get salt solution.

polar solvent : The angle of which the molecules of compounds come together is around 105 degrees, making it like a triangle. Example will be water and it can only dissolve other polar substances. This is why oil cannot be dissolve in water but salt can.

non-polar solvent: The way the molecules of a compound come together is like a circle with one type of molecule in the interior and another in the exterior. An example would be oil and gasoline. It can only dissolve other non polar substances and not polar substances.

Hydrophobic: Meaning that the substance cannot be dissolved in water.

Hydrophilic: Meaning that this substance can be dissolved in water very well.

Separating funnel: This is a tool used to separate liquids that cannot be dissolved, like oil and water. After pouring the mixture in and shaking, allow it to settle and it will form 2 separate layers of liquid, based on density, like the less dense one on top and the more dense one below, in this case, water below and oil on top. You can then open the tap below and allow the water to flow into a beaker, then close the tap and open again to allow the oil to flow into another beaker.

Buchner filtration: It is to reduce the pressure of the surrounding for a solid to be easily extracted from a liquid. The solid will be trap in the filter while the liquid will flow into a flask below.

It is different from regular filtration with filter paper as it will take a longer time, while Buchner filtration is faster.

By: Brendon Goh

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