Hey there! Sign in to join this conversationNew here? Join for free
    • Thread Starter
    Offline

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

    J03. 2c paper 3 chem !!
    PLease help with moles

    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=
    Use your answer to (c)(i).
    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.
    • Community Assistant
    • Study Helper
    Offline

    15
    ReputationRep:
    Community Assistant
    Study Helper
    (Original post by justwork)
    http://papers.xtremepapers.com/CIE/C...0_s03_qp_3.pdf

    J03. 2c paper 3 chem !!
    PLease help with moles

    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=
    Use your answer to (c)(i).
    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 ...
    • Thread Starter
    Offline

    0
    ReputationRep:
    (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 ?
    • Community Assistant
    • Study Helper
    Offline

    15
    ReputationRep:
    Community Assistant
    Study Helper
    (Original post by justwork)
    So is vol of co2 = 44 dm3 ?
    I should read the question again rather more carefully ... :eek:
    • Thread Starter
    Offline

    0
    ReputationRep:
    Would it be 44/1000 x 24 ?
    • Thread Starter
    Offline

    0
    ReputationRep:
    (Original post by charco)
    I should read the question again rather more carefully ... :eek:
    Is it a joke or for real ?
    Offline

    15
    ReputationRep:
    I thought this was going to be a help save the moles kind of thread...

    Name:  mole1245.jpg
Views: 450
Size:  20.3 KB
    • Community Assistant
    • Study Helper
    Offline

    15
    ReputationRep:
    Community Assistant
    Study Helper
    (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 ...
    • Community Assistant
    • Study Helper
    Offline

    15
    ReputationRep:
    Community Assistant
    Study Helper
    (Original post by justwork)
    Is it a joke or for real ?
    For real ...
    • Thread Starter
    Offline

    0
    ReputationRep:
    Ok so i have done for q1 = 0.24/ 24 = 0.01
    but for q2 when they say about Caco3 this puzzles me !
    • Community Assistant
    • Study Helper
    Offline

    15
    ReputationRep:
    Community Assistant
    Study Helper
    (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=
    • Thread Starter
    Offline

    0
    ReputationRep:
    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 ?
    • Thread Starter
    Offline

    0
    ReputationRep:
    ???
    Offline

    0
    ReputationRep:
    http://papers.xtremepapers.com/CIE/C..._1+2+3+5+6.pdf

    Paper 3 Pg 2 question 2 (c)
 
 
 
Poll
Do you agree with the PM's proposal to cut tuition fees for some courses?

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.