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Chemistry Paper 1 problems...

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nox_fjmoony:
I was solving the may/june 2008 question paper yesterday and I had problems with these questions:

6,10,13,17,20,23,25,26,27,28,32 and 40

Anyhelp would definitely be appreciated, along with an explanation of the solution, yeah. Thanks all.
Ciao
:)

nox_fjmoony:
Anyone? Need some help here, please  :-\

nid404:
oh my!

too many...I'll do them by tom  :)

tmisterr:
6. 1cm3 of 1g/cm3=1g of water. you know that at 25 degrees and 1 atm it occupies 24 dm3. Use pV=nRT to find R (T in K, Volume in m3 and p in Pa 1atm=101kpa). R is 8.134.....
now use this value of R to find the volume of the water at 596k. V= 2.67dm3

10. using hess's law, you can either first form TiO2 and C then form Ti and CO(this second part is the enthalpy change of the reaction) or you can directly form Ti and CO from the raw elements Ti, C, and O2. the two enthalpy changes should be equal. therefore since 2 moles of CO are formed, 2*-110=-940 + enthalpy change. so enthalpy change is equal to +720

13. this is Na2O  Mg(OH)2 is only partially soluble so it will be a weak alkali and the other two will form acidic solutions. (revise chemical periodicity, it will help you on this type of questions)

17. when an ammonium salt is heated with an alkali, ammonia is liberated do lime-water is calcium hydroxide which is an alkali and the only alkali on the list

20. number 20 should be B. alkenes undergo electrophilic substitution, then the haloalkane will undergo neucleophilic addition.

23. this is clearly D, pentane cannot be cracked to a hydrocarbon with a longer carbon chain!!

24. Sn1 will be for tertiary halogenoalkanes since these are stabilised by three methyl groups so the reaction can take part in two stages.

I have to go though

nox_fjmoony:
@tmisterr: Hey thankyou soo much for all your help man :D Really appreciate it, but could you answer one question? Its like, isn't R a constant? And so why do we have to manually find out the value of R, when we already know it? Just a bit confused really. Thanks.

And can anyone help me with the remaining questions?

Right, thanks all.

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