

2002 - Written Paper - Q4(b)
Started by someone11, May 24 2006 10:48 PM
11 replies to this topic
#1
Posted 24 May 2006 - 10:48 PM
Hello
yea sorry i get it now, it was late i was rambling.
I actually havea genuine question about 2002, question 4b)
The reaction FeS and FeCl -----> H2S + FeCl
In FeS iron is sometimes present as an impurity. Name the other product which would be formed in the reaction with dilute hydrochloric acid if iron metal is present as an impurity.
The answr is hydrogen but how?????
yea sorry i get it now, it was late i was rambling.
I actually havea genuine question about 2002, question 4b)
The reaction FeS and FeCl -----> H2S + FeCl
In FeS iron is sometimes present as an impurity. Name the other product which would be formed in the reaction with dilute hydrochloric acid if iron metal is present as an impurity.
The answr is hydrogen but how?????
#2
Posted 25 May 2006 - 11:54 AM
Well..im nto any good at chemistry....but i dont know where the 0.02 moles came from for the H2SO4....
moles= concentration * Volume
both acids have the same concentration and volume..so they surely have the same number of moles...
ya if someone would help out it be nice..im a tad confused here too
moles= concentration * Volume
both acids have the same concentration and volume..so they surely have the same number of moles...
ya if someone would help out it be nice..im a tad confused here too
#3
Posted 25 May 2006 - 01:11 PM
both acids have the same concentration and volume..so they surely have the same number of moles...
Yeah I'd agree with that
Someone11, you confused me a wee bit


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#4
Posted 25 May 2006 - 03:51 PM
Can you give the question in context (or PM me it) because I don't quite understand what you mean.
#5
Posted 25 May 2006 - 04:08 PM
This is a bit of a guess so check with someone else but... has it got something to do with the fact that there are 2H in H2SO4, whereas most other acids only have one H like HNO3? That might alter the number of moles reacting?
I'm not sure but I remember being told that H2SO4 is different because of the 2H.
Sorry if that's utter rubbish!
I'm not sure but I remember being told that H2SO4 is different because of the 2H.
Sorry if that's utter rubbish!
The race is long, and in the end it's only with yourself.
#6
Posted 25 May 2006 - 04:15 PM
that is true...i can't remember what difference exactly the 2nd H makes though....i've got a feeling it's got something to do with how quick it reacts...can't remember though

#7
Posted 25 May 2006 - 04:20 PM
isn't the H2 part of H2SO4 called it's something power? you know, you use it in N1C1V1 = N2C2V2... i had a feeling it was called the neutralising power? or power of the acid?
#8
Posted 25 May 2006 - 04:54 PM
Ok, I think I know what you're trying to get at but if im wrong tell me.
Lets take 2 equations one involving sulphuric acid and one involving hydrochloric acid:
NaOH + HCl ----> NaCl + H2O In this equation 1 mole of alkali neutralises one mole of acid.
However if you take the balanced equation for H2SO4 it looks like this:
2NaOH + H2SO4 -------> Na2SO4 + 2H2O
Technically they require the same moles of alkali as the ratio is still 1:1 however the power of the sulphuric acid is 2. Therefore as there are 2 H+ ions there are 2OH- ions but the ratio remains the same.
Lets take 2 equations one involving sulphuric acid and one involving hydrochloric acid:
NaOH + HCl ----> NaCl + H2O In this equation 1 mole of alkali neutralises one mole of acid.
However if you take the balanced equation for H2SO4 it looks like this:
2NaOH + H2SO4 -------> Na2SO4 + 2H2O
Technically they require the same moles of alkali as the ratio is still 1:1 however the power of the sulphuric acid is 2. Therefore as there are 2 H+ ions there are 2OH- ions but the ratio remains the same.
#9
Posted 25 May 2006 - 05:08 PM
Or, if you take 2001 section A Q3,
Answer is D because
PCVacid = PCValkali
2x0.3x0.01 = 1x0.3x0.02
Answer is D because
PCVacid = PCValkali

#10
Posted 25 May 2006 - 07:27 PM
if you can give the full question maybe someone can help?
#11
Posted 26 May 2006 - 04:12 PM
I did that question recently. All i did was look at the diagram there, and there were bubbles cumin out, and if u look at the equation the only gas that could be formed is hydrogen. Thats all there is to it really. Plus its only 1 mark.
#12
Posted 27 May 2006 - 12:01 PM
I did that question recently. All i did was look at the diagram there, and there were bubbles cumin out, and if u look at the equation the only gas that could be formed is hydrogen. Thats all there is to it really. Plus its only 1 mark.
There is no diagram.


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