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Archive for the ‘school’ Category

diamond vs graphite.

Enthalpy of combustion Kcal/mole

Graphite 93.983
Diamond 94.437

http://www.madsci.org/posts/archives/Dec2002/1039805494.Es.r.html

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By S Ramesh, Channel NewsAsia | Posted: 12 November 2006 1925 hrs

SINGAPORE: The Singapore Examinations and Assessment Board has made adjustments to the timing of some examination papers for the GCE O and A levels on the 16th and 17th of this month.

This is in view of possible travel delays due to traffic arrangements to facilitate US President George Bush’s visit to Singapore.

The move is to ensure the candidates reach their exam centres on time.

On 16th November, time adjustments have been made to the O level Additional Mathematics and A Level Geography papers, while on 17th November, there are time adjustments to the O Level Food and Nutrition and Principles of Accounts papers and the A level Further Mathematics and Divinity papers. – CNA /dt

(um. wat’s divinity? isnt that a subject at hogwarts?)
(hey. unfair. wat abt my chem paper?)
(and why is bush coming?)

http://www.channelnewsasia.com/stories/singaporelocalnews/view/240915/1/.html

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behold the magnetic H.

“However, different 1H or 13C nuclei absorb at slightly different frequencies. This difference results from differences in the small internal magnetic field Be for each 1H or 13C nucleus. Again, the Be field results from the circulation of electrons of the molecule. Different 1H or 13C nuclei have different electron density surrounding them and consequently, are shielded from the applied field Bo by Be fields of different magnitude. Remember, differences in (Bo-Be) translate into differences in the frequency needed to cause the nuclear spin transitions..”

http://orgchem.colorado.edu/hndbksupport/nmrtheory/chemshift.html

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aq. NaBr.

“Electrolysis of an aqueous solution of NaBr will produce hydrogen at the cathode, as the aqueous sodium sulfate solution did, because neither Na+(aq) nor Br-(aq) can be reduced at potentials which are less negative than standard hydrogen. The electrolysis of aqueous NaBr solutions will produce bromine at the anode because the standard potential of bromide oxidation is less positive than that of the oxidation of water.”

http://www.ualberta.ca/~jplambec/che/p102/p02112.htm

ahhhh. i wrote water discharged!! haha. fine.

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