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unknown 101:

--- Quote from: emi on May 29, 2009, 02:34:15 pm ---i apologize if you find it insulting .  im sorry

--- End quote ---

hahaha, im just messing around , alrigth then ill try my best to explain each part

number of moles of NiCO3 = 0.08 mols
cuz its says that the number of moles of sulphuric acid in 40cm3 of 2.0 mol/dm3 = 0.08 mol

and the reaction goes like this

NiCO3 + H2SO4 ---->  NiSO4  + CO2   +  H2O

only 1 mol of   NiCO3 reacted not 2 or 3 cuz if it was it would be : 2NiCO3 or anything else
and also 1 mol of H2SO4 reacted

so if 1 mol of H2SO4 is 0.08 (like it mentions) that means also 0.08 mol of nickel carbonate reacted
because it is 1:1 ratio

did u get the first part?

emi:
ahhaa ,, so because they want more i only have to see how much moles they have right ?
we can see that H2SO4 is one mole and its mole is 0.08 
so if NiCO3 is also one more then it will also be 0.08


right ?

tell me if i pass this part

emi:
but the Question says " an excess of nickle carbonate 12g was added to 40cm3 of sulphuric acid , 2 mol/dm3"

what do they mean by 2 mol/dm3

Shogun:
first,in qi) in the question was given tht 40 cm3 of 2.0 mole per dm cube of nickle carbonate
now use the equation concentration x colume in dm 3 to get the number of mole of nickle carbonate. but first the volume is given in cm3 u have to convert it by deviding by 1000 to dm3
so it wuld be: 40cm3/ 1000 = 0.04dm3
now use tht first formula 2 x 0.04= 0.08 moles

qii) here its cross multiplication so it would be like 1 mol gave u 119g how much would 0.08 moles give u?
so it would be :
no. of moles                      mass produced
       1                                    119
       0.08                                  ?

so 0.08 x 119= 9.52g

qiii)now they said total reacted was 12g but was in excess, and we found out tht 9.52g was really reacted so wat was left of it was the unreacte nickel carbonate. (i. subtraction)
so it would be : 12-9.52= 2.48g

now i)  ill explain it after i come back, srry i have to go some where, ill return in about 10 mins

Shogun:

--- Quote from: emi on May 29, 2009, 02:52:39 pm ---but the Question says " an excess of nickle carbonate 12g was added to 40cm3 of sulphuric acid , 2 mol/dm3"

what do they mean by 2 mol/dm3



--- End quote ---

tht 2 is the concentration of nickel carbonate

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