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Chemistry Help HERE ONLY !!
heat619:
Is the pressure for the Contact Process 10 atm or 20 atm, cuz the mark scheme says 10 but the book says 20 :S
Shogun:
here it is
(ii)one piece of marble 0.3g, was added to 5cm3 of hydrochloric acid, concentration 1.00 mol/dm3. which reagent is in excess? give reason for your answer.
mass of one mole of CaCO3 =100g
number of moles of CaCO3= .................................................................
number of moles of HCl=.......................................................
regent in excess is ...........................................................
reason....................................................................
[4]
(iii) use your answer to (ii) to calculate the maximum volume of carbon dioxide produced measured at r.t.p.
...[1]
explain to me what u have to do, plz dont just give me the answer, do explain every part on how to find the excess.
Thanks
Ibiza279:
--- Quote from: heat619 on May 31, 2009, 05:18:56 pm ---Is the pressure for the Contact Process 10 atm or 20 atm, cuz the mark scheme says 10 but the book says 20 :S
--- End quote ---
huh we learnt it was 1 atp not 10 or 20 n i checked wikipedia too they say its 1-2 atp so the rite answer is 1 atmospheric pressure
thukon:
@shogun. CaCO3= 40+12+16+16+16= 100
Number of moles of CaCO3 = 0.3/100= 0.003
Number of moles of HCL = 1 mol per dm3, and 1000cm3 = 1 dm3. 5/1000= 0.005
The reaction needs 1 mol of CaCO3 and 2 mols of HCl. So the HCl needs to be double the the CaCO3, but here there isnt enough, because the CaCO3 is 0.003, and the HCl needs to be 0.006, but its only 0.005. So CaCO3 is in excess.
I was kinda confused myself doing the question. Check with the mark scheme and tell me if im correct. If i am, +rep me PLZ. I REALLY NEED IT!!
XGhostX:
People i have found this site .....Hope its useful..... http://www.chemactive.com/grade_10.html :P
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