Chemical Forums
Chemistry Forums for Students => High School Chemistry Forum => Topic started by: huskywolf on November 15, 2009, 01:14:56 PM
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Why does Al liberate more H2 from HCl than calcium?
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Kitchen foil was put in HCl and liberated more H2 gas than calcium-HCl.is kitchen foil Aluminium oxide?is that why more H2 is produced
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You were already explained twice in the previous thread why amount of metals matters, yet you are still repeating the same mistake and ask 'which metal gives more product'. This is a nonsensical question.
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the amount of Al 5g was the same amount of Ca 5g,I wan to know why the hell Al liberates ALOT more Hydrogen gas !You didnt explain that did you?
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It must be something that is in the alu foil(kitchen foil)?the protective oxide layer or is there trapped hydrogen in the alu foil???
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You didnt explain that did you?
No, but the question now - 5g vs 5g - makes sense.
Do you know whow to write reaction equations for both cases?
It must be something that is in the alu foil(kitchen foil)?the protective oxide layer or is there trapped hydrogen in the alu foil???
No, answer lies in the molar masses of both metals and their valences.
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yes
Ca + 2HCL=CaCl2 + H2
Al + 2HCL=AlCl2 + H2?
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or should it be 2Al + 6HCl = 2AlCl3 + 3H2?
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or should it be 2Al + 6HCl = 2AlCl3 + 3H2?
Much better now.
Looking at these equations, can you tell how many moles of H2 are produced per mole of Al? Per mole of Ca?
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2Al + 6HCl = 2AlCl3 + 3H2
2 mol al : 3 mol Hydrogen gas
Thank you!
1 more question
what are the ways I could determine the amount of acid consumed in a displacment reaction like these?
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2Al + 6HCl = 2AlCl3 + 3H2
2 mol al : 3 mol Hydrogen gas
Thank you!
You have not answered my question - and at the moment we are still talking about moles, not masses, but if knowing that 2 moles of Al produce 3 moles of H2 makes you happy - that's OK with me. Just note it doesn't address your original problem.
what are the ways I could determine the amount of acid consumed in a displacment reaction like these?
The same way you can calculate amount of hydrogen produced - calculating number of moles and using stoichiometry as defined by the balanced reaction equation.
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sorry,ok so that would mean that more H2 gas would be liberated because 0.66 mole of Al would produce 1 mol of Hydrogen? so more hydrogen gas is produced than Ca would because Ca-H mole ratio is 1:1,so that would be the reason?
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That would be the reason for equimolar amounts. For identical masses you should take into account also molar masses - 5 g of which metal means more moles of metal?
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That would be the reason for equimolar amounts. For identical masses you should take into account also molar masses - 5 g of which metal means more moles of metal
As Calciums atomic weight is 40 and Al's atomic weight is 27
n=m/M so n(al)=5/27=0.185 gmol
n(Ca)=5/40=0.125gmol
5g of Al =more moles of metal sir?
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Yes.
And don't sir me :)
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Thank you for your help
goodnight
:)
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Actually 1 more question please. 5g Ca added to HCl
using the weight of the metal used and moles of H2gas produced calculate the atomic weight of the metal.
so for Ca
n=V/Vm, n(h2)=0.232L/24.1Lmol so 0.010 mol (H2)
M=n/m ,M(Ca)=0.010mol/0.5g=0.02gmol? {M=atomic weight}
0.02gmol could not be the atomic weight of calcium in this reaction could it?
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M=n/m
That's incorrect.
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Our tutor gaves us that...I thought he was wrong
Could you tell me what the correct formula is to calculate atomic weight from lab data gathered Please