Qualification > Sciences
IGCSE CHEMISTRY DOUBTS
Ivo:
--- Quote from: 8T on June 04, 2010, 06:31:48 pm ---May june 08 q 8 b 3 the first one my answer was N-H & C=O bonds is it correct & if not what is ?
the second one i dnt quite get what the ms says ??
--- End quote ---
Just say:
Similarity: They both have an amide linkage.
Difference: The protein has many different monomers (of amino acids) whereas the synthetic polyamide has only two monomers (dicarboxylic acid and diamine).
I did this paper as a mock and my teacher marked it, full marks for this section.
Ivo:
--- Quote from: 8T on June 04, 2010, 06:26:37 pm ---Could someone rexplain please may june 04 q4 b 2 ( i didnt get Ivo's explanation) and b 3 ??
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What specifically did you not get, I can try and elaborate.
And for iii) The graph would rise to maximum height, then decrease to zero again. Why? Well because aluminium hydroxide (the product formed) dissolves in excess. Think of the test for aluminium cation: add aqueous sodium hydroxide, soluble in excess giving a colourless solution. Same applies here, when a small volume was added, there was precipitate, as you add more and more, it goes colourless, therefore no precipitate. The common mistake is to think of reactivity.
I hope that clears the issue somewhat. :D
8T:
Oh for b 3 that was perfect mate :D
But b 2 the only thing i get is that iron 2 is more reactive period. xD
Could u try and elaborate as u said????
8T:
--- Quote from: Ivo on June 04, 2010, 06:35:22 pm ---Just say:
Similarity: They both have an amide linkage.
Difference: The protein has many different monomers (of amino acids) whereas the synthetic polyamide has only two monomers (dicarboxylic acid and diamine).
I did this paper as a mock and my teacher marked it, full marks for this section.
--- End quote ---
U seem to make it very easy to understand i already have + rep u :D
Ivo:
--- Quote from: 8T on June 04, 2010, 06:45:44 pm ---Oh for b 3 that was perfect mate :D
But b 2 the only thing i get is that iron 2 is more reactive period. xD
Could u try and elaborate as u said????
--- End quote ---
What, so you don't get why it's Fe(OH)2?
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