Qualification > Sciences
Chemistry P3 7/6/2010
J.Darren:
Addition polymerisation - Only produces the polymer
Condensation polymerisation - Produces water and polymer
Uses of polymers :
Nylon and terylene - make clothes
Nylon - rope making
PVC - electrical insulator and pipes
Poly(ethene) - bowls, buckes and plastic bags
Plastic and pollution :
- Source of visual pollution
- Burning produces toxic gas
Nylon and proteins :
C=O-OH and NH2 monomers
Proteins has many monomers as it is a biological polyamide, whereas synthetic polyamide, such as nylon, only contains the aforementioned monomers.
When they are joined together, an amide linkage C=O-NH is formed, water is eliminated in forming this linkage.
Amino acids -> Water + Protein (Condensation polymerisation)
Water + Protein -> Amino acids (Hydrolysis, boil with hydrochloric acid)
Polyesters :
C=O-OH and OH monomers
When they are joined together, an ester linkage C=O-O is formed, water is eliminated in forming this linkage.
Fats :
Animal fats and vegetable oils are esters.
Fat (Glyceryl sterate) + Sodium hydroxide -> Sodium salt of long-chain organic acid (Sodium sterate) + Glycerol
J.Darren:
Carbonhydrates :
Contains only Carbon, Hydrogen and Water.
The ratio of Hydrogen to Oxygen atoms is in 2:1 ratio.
Glucose - C6H12O6
Starch - (C6H10O5)n
Two OH monomers were joined to form Starch :
-O-[]-O-[]-O-[]-
Glucose -> Starch + Water (Condensation polymerisation)
J.Darren:
Acid hydrolysis of complex hydrocarbons :
Heated with dilute HCl, the acid is a catalyst in this reaction.
Starch + Water -> Glucose
The reaction can be catalysed by enzymes, but the sugar produces would be different.
Fermentation :
Glucose -> Ethanol + Carbon Dioxide
Catalysed by enzymes from yeast.
The reaction is an anaerobic respiration of yeast cells, oxygen in air would oxidise ethanol to carbon dioxide.
35 degree celsius - optimal temperature. Too high - enzymens gets denatured. Too low - rate would be too slow to be economical.
Fermentation ceases when the concentration of ethanol reaches 14%, this is because ethanol is poisonous to yeast, and at this concentration yeast dies. All the glucose has been used up.
C6H12O6 -> 2C2H5OH + 2CO2
Helium:
--- Quote from: soraam on June 05, 2010, 11:17:45 am ---its easier if you memorized knaca mgal czn fe pb hcu agau if youre arab youll see what i mean
and now my question
how do you know wich is the limiting reagent if the mole ratio is NOT 1:1 :) :)
--- End quote ---
ya i heard that one before, i heard a chemistry teacher saying,
knaca thin and age of lead...
sarasa:
--- Quote from: J.Darren on June 05, 2010, 03:12:00 pm ---Acid hydrolysis of complex hydrocarbons :
Heated with dilute HCl, the acid is a catalyst in this reaction.
Starch + Water -> Glucose
The reaction can be catalysed by enzymes, but the sugar produces would be different.
Fermentation :
Glucose -> Ethanol + Carbon Dioxide
Catalysed by enzymes from yeast.
The reaction is an anaerobic respiration of yeast cells, oxygen in air would oxidise ethanol to carbon dioxide.
35 degree celsius - optimal temperature. Too high - enzymens gets denatured. Too low - rate would be too slow to be economical.
Fermentation ceases when the concentration of ethanol reaches 14%, this is because ethanol is poisonous to yeast, and at this concentration yeast dies. All the glucose has been used up.
C6H12O6 -> 2C2H5OH + 2CO2
--- End quote ---
Oxygen will oxidise ethanol 2 ethanoic acid, da atmospheric oxygen is not enough to oxidise it to CO2....! da rest r impressive, great work!!!
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