Author Topic: chemistry papers 1 help  (Read 640 times)

Offline ruby92

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chemistry papers 1 help
« on: June 05, 2010, 10:22:01 pm »
o/n 2004 28 10 23 3 (why not D)
m/j 2005 25 27
m/j 2006 32(2??) 10 11 25

Offline Sue T

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Re: chemistry papers 1 help
« Reply #1 on: June 06, 2010, 08:25:34 am »
« Last Edit: June 06, 2010, 08:36:35 am by Sue T »
Knowledge is knowing a tomato is a fruit; Wisdom is not putting it in fruit salad.

Offline Sue T

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Re: chemistry papers 1 help
« Reply #2 on: June 06, 2010, 08:42:42 am »
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-
« Last Edit: June 06, 2010, 09:01:33 am by Sue T »
Knowledge is knowing a tomato is a fruit; Wisdom is not putting it in fruit salad.

Offline ruby92

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Re: chemistry papers 1 help
« Reply #3 on: June 07, 2010, 11:48:55 am »
THANK YOU SOOO MUCH  ;D ;D ;D