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# Help moles !!! watch

1. http://papers.xtremepapers.com/CIE/C...0_s03_qp_3.pdf

J03. 2c paper 3 chem !!

Each tablet contains the same number of moles of CaCO3 and MgCO3. One tablet reacted with excess hydrochloric acid to produce 0.24 dm3 of carbon dioxide at r.t.p.
CaCO3 + 2HCl → CaCl2 + CO2 + H2O
MgCO3 + 2HCl → MgCl2 + CO2 + H2O
(i)Calculate how many moles of CaCO3 there are in one tablet.
number of moles CO2=
number of moles of CaCO3 and MgCO3 =
number of moles of CaCO3=

.............. .............. ..............
(ii)Calculate the volume of hydrochloric acid, 1.0 mol / dm3, needed to react with one tablet.
number of moles of CaCO3 and MgCO3 in one tablet=
number of moles of HCl needed to react with one tablet =
volume of hydrochloric acid, 1.0 mol / dm3, needed to react with one tablet=

.............. .............. ..............
[2]

MY first hard problems are the red ones, then the purple ones.
2. (Original post by justwork)
http://papers.xtremepapers.com/CIE/C...0_s03_qp_3.pdf

J03. 2c paper 3 chem !!

Each tablet contains the same number of moles of CaCO3 and MgCO3. One tablet reacted with excess hydrochloric acid to produce 0.24 dm3 of carbon dioxide at r.t.p.
CaCO3 + 2HCl → CaCl2 + CO2 + H2O
MgCO3 + 2HCl → MgCl2 + CO2 + H2O
(i)Calculate how many moles of CaCO3 there are in one tablet.
number of moles CO2=
number of moles of CaCO3 and MgCO3 =
number of moles of CaCO3=

.............. .............. ..............
(ii)Calculate the volume of hydrochloric acid, 1.0 mol / dm3, needed to react with one tablet.
number of moles of CaCO3 and MgCO3 in one tablet=
number of moles of HCl needed to react with one tablet =
volume of hydrochloric acid, 1.0 mol / dm3, needed to react with one tablet=

.............. .............. ..............
[2]

MY first hard problems are the red ones, then the purple ones.
If you work out the total moles of CO2 from the gas laws (mol = vol/24dm3) you can see that the moles of each carbonate is half that value ...
3. (Original post by charco)
If you work out the total moles of CO2 from the gas laws (mol = vol/24dm3) you can see that the moles of each carbonate is half that value ...
So is vol of co2 = 44 dm3 ?
4. (Original post by justwork)
So is vol of co2 = 44 dm3 ?
I should read the question again rather more carefully ...
5. Would it be 44/1000 x 24 ?
6. (Original post by charco)
I should read the question again rather more carefully ...
Is it a joke or for real ?
7. I thought this was going to be a help save the moles kind of thread...

8. (Original post by justwork)
Would it be 44/1000 x 24 ?
I should read the question again rather more carefully ...

There are NOT 44 dm3 of carbon dioxide ...
9. (Original post by justwork)
Is it a joke or for real ?
For real ...
10. Ok so i have done for q1 = 0.24/ 24 = 0.01
but for q2 when they say about Caco3 this puzzles me !
11. (Original post by justwork)
Ok so i have done for q1 = 0.24/ 24 = 0.01
but for q2 when they say about Caco3 this puzzles me !
You really do not want to read the question carefully do you?

Each tablet contains the same number of moles of CaCO3 and MgCO3. One tablet reacted with excess hydrochloric acid to produce 0.24 dm3 of carbon dioxide at r.t.p.
CaCO3 + 2HCl → CaCl2 + CO2 + H2O
MgCO3 + 2HCl → MgCl2 + CO2 + H2O
(i)Calculate how many moles of CaCO3 there are in one tablet.
number of moles CO2=
number of moles of CaCO3 and MgCO3 =
number of moles of CaCO3=
12. So for Caco3 and Mgco3 is 0.01 ?
But what about the q3 Caco3 ? In Mark scheme its written 0.05 ? How can i get that answer ?
13. ???
14. http://papers.xtremepapers.com/CIE/C..._1+2+3+5+6.pdf

Paper 3 Pg 2 question 2 (c)

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