• We need your support!

    We are currently struggling to cover the operational costs of Xtremepapers, as a result we might have to shut this website down. Please donate if we have helped you and help make a difference in other students' lives!
    Click here to Donate Now (View Announcement)

CheMistry

Messages
383
Reaction score
19
Points
28
25cm square of1.5mol/dm2 of HCL was used.
2Hcl +CaCO3----->CaCl2+h2O+CO2

How many volume of carbon dioxide is made at RTP?

Marking Scheme says 0.9dm wheras I am getting 0.45
 
Messages
4,609
Reaction score
3,903
Points
323
well my answer is also 0.45 dm3 ........... what i think is that they (examiners) have not taken the number of moles of those substances into consideration......if we do the same calculation with 1 mole of HCL unlike here where 2 moles are given , we will get 0.9 dm3. OR IT MIGHT HAVE BEEN THEIR MISTAKE! :p
 
Messages
732
Reaction score
27
Points
26
yes there is a Problem in the marking scheme the answer is 0.45 dm^3


SAUD ASLAM said:
25cm square of1.5mol/dm2 of HCL was used.
2Hcl +CaCO3----->CaCl2+h2O+CO2

How many volume of carbon dioxide is made at RTP?

Marking Scheme says 0.9dm wheras I am getting 0.45

Saud it's Volume so it should cm CUBE and dm^3

NOT

Cm Square and dm^2
 
Messages
732
Reaction score
27
Points
26
Chem_master said:
hmmm.....quite difficult well according to my answer the volume is 1.8 dm3

Chemistry Master what happened to you ! :shock:

your Answer is not even close to the actual answer !

please show me the method you adopted to carry out the answer so that i could point out where you did the mistake :)
 
Messages
134
Reaction score
2
Points
0
well calculating the mols of HCL
1.5=mols/0.025
mols=0.0375
mols of CO2= 0.01875
mols of CO2=vol/24dm3
vol of CO2 = 0.45 dm3.......oh my bad i thnk so my calculator had gone down......srryyy... :|
 
Messages
383
Reaction score
19
Points
28
UxaiR said:
yes there is a Problem in the marking scheme the answer is 0.45 dm^3


SAUD ASLAM said:
25cm square of1.5mol/dm2 of HCL was used.
2Hcl +CaCO3----->CaCl2+h2O+CO2

How many volume of carbon dioxide is made at RTP?

Marking Scheme says 0.9dm wheras I am getting 0.45

Saud it's Volume so it should cm CUBE and dm^3

NOT

Cm Square and dm^2
Ya,kabhi kabhi ho jata hai
 
Messages
732
Reaction score
27
Points
26
No problem i was just making you little conscious :)
these little things are not tolerated by Cambridge so be careful Next time :)
 
Messages
100
Reaction score
11
Points
28
hmmm>>>....eXAMNER IS WRONG THIS TIME
mOLES of HCL:
0.0375

Volume of CO2:
0.01875*24dm^3=0.45dm^3
 
Messages
732
Reaction score
27
Points
26
Silent Hunter said:
donno how examiners can be wrong but they are this time ;) :p
they can , they too are humans Just like Us :)
and i have Seen mistakes of these types in marking Schemes :)
 

Nibz

XPRS Moderator
Messages
4,615
Reaction score
9,574
Points
523
Examiners can be wrong sometimes, but when they are, they do mention their mistake!!
 

XPFMember

XPRS Moderator
Messages
4,555
Reaction score
13,290
Points
523
SAUD ASLAM said:
25cm square of1.5mol/dm2 of HCL was used.
2Hcl +CaCO3----->CaCl2+h2O+CO2

How many volume of carbon dioxide is made at RTP?

Marking Scheme says 0.9dm wheras I am getting 0.45


I just viewed the mark scheme..and i've found the mistake...
we need to divide the no. of moles of HCl by 2 to get the no. of moles of CO2 since as per the eqn. 2 moles of HCl gives 1 mol. of CO2...and this is what nt done in the marking scheme :)
 
Top