Tuesday, April 14, 2009

While searching

Group photo =)


CHEM PROJECT:


Dettol, made from alcohol, contains, Chroloxylenol.




Dove conditioner, containing dimetheiconol.




Sheng siong.


































Thursday, April 9, 2009

What is an alcohol?

In chemistry, an alcohol is an organic compound in which a hydroxyl group (-OH) is bound to a carbon atom of an alkyl or substituted alkyl group. The general formula for alcohols homologous series is CnH2n+1OH (when n ≥ 1). In common terms, the word alcohol refers to ethanol, the type of alcohol found in alcoholic beverages. There are three major subsets of alcohols: primary (1°), secondary (2°) and tertiary (3°), based upon the number of carbon atoms the C-OH group's carbon (shown in red) is bonded to.





No. of Carbon atoms (C):
Name of Alcohols (-ol):
Alcohols formula (CnH2n+1OH):

  • 1 C atom
    Methanol
    CH3OH
  • 2 C atoms
    Ethanol
    C2H5OH
  • 3 C atoms
    Propanol
    C3H7OH
  • 4 C atoms
    Butanol
    C4H9OH
  • 5 C atoms
    Pentanol
    C5H11OH


Alcohols are covalent molecules with physical properties of:
- colourless liquids
- have low boiling points
- soluble in water
As no. of carbon atoms increases, boiling points, melting points and the density of alcohols increase too but their solubility in water decreases.
Uses of ethanol:
i) making alcoholic drinks
ii) industrial solvent
iii) making perfume