IGCSE/GCSE/O & A Level/IB/University Student Forum
Qualification => Subject Doubts => GCE AS & A2 Level => Sciences => Topic started by: ruby92 on June 05, 2010, 10:22:01 pm
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o/n 2004 28 10 23 3 (why not D)
m/j 2005 25 27
m/j 2006 32(2??) 10 11 25
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w_04 Q)28 : read this http://www.chemguide.co.uk/mechanisms/elim/dhcomplex.html#top
Q)23 attached
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Q 3) 10cm3 of CO2 and 10cm3 of SO2 are formed then at room temp water is a liquid so we dont consider it
there is 30cm3 excess of O2 (cuz 1 mole of methanethiol reacts with only 3 moles of O2 but they said 60cm3 wer we only need 30cm3) so add it all up 10+10+30=50 th ans is C !
s_05 Q)25 : a primary alcohol gets oxidised 2 an aldehyde so step1 MUST be oxidation n step 3: the secondary alcohol became a ketone which is oxidation now b careful ther cuz: CH3CH2OCH(OH)CH3 already has tht 'O' if it dint then it would be esterification
Q)27 : a primary alcohol gets fully oxidised in2 a carboxylic acid. So if it reacts with th carboxylic acid an ester is formed (which is sweet-smelling)! <hope thts clear>
2006 Q) 32 : 1)standard enthalpy change of atomisation : when 1 mole of gaseous atoms are formes from one mole of the element in its standard state
2) first ionisation energy of anything can be represented like this : X(g) --> X+ + e-
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THANK YOU SOOO MUCH ;D ;D ;D