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chem question

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Bani:

--- Quote from: mousa on September 18, 2009, 03:20:01 pm ---yup.. thats right,i got the same answerss


--- End quote ---

Yippeeee!
yup they are right!
thanks guys!

Q80BOY:
heyy guyz !!

my chem teacher is letting us live in hell! :P Moles and moles and more moles!

i need ur help in a couple of questions:

1. 0.0185 mol of hydrated MgSO4.xH2O has a mass of 4.56g. Calculate the number of molecules of water of crystallisation in the salt.

ur help is highly appreciated!! :D

nid404:
ok here u go

Mass og 1 mol of MgSO4=120g
mass of 0.0185mol=120X0.0185=2.22g
Mass of water=4.56-2.22=2.34g
1 mole of water=18g
there x moles= 2.34
no of moles of water in 0.0185 moles of hydrated magnesium sulphate=0.13
therefore no of moles of water=0.13/0.0185=7 moles
therefore MgSO4.7H2O

Cross check
Mass of 1 mole of MgSO4.7H2O=246g
4.56g= how many moles
cross multiply
gives 0.0185 moles

Q80BOY:
thnxxxx :)

Q80BOY:
heloooo .. its me again :P

i got a part of a question i need help with ..

in the following reaction ..

2NaOH + H2SO4 --> Na2SO4 + 2H2O

what would be observed if peices of red and blue litmus paper were added to Sodium sulfate after the reaction?

ur help is highly appreciated guyzz!! :D

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