[just_smile_more]

you need all the acid to react so you can compare the amount of gas given off for each acid, if it was the other way round you would find out gas given off for a certain amount of metal, or at least that is my understanding

Thank you, I understand now
Just one more question; in the titration would you place the H2SO4 or the base (NaOH) in the burette because I was always taught to place the substance you know the most about in the burette but I know the same amount about both substances so I don't know which substance to put where? Can anyone help?

Thanks

[hatter]

thanks for the gas stuff guys

the titrations is simpler, or atleast in my opinion. i used this equation:
2NaOH(aq) + H2SO4(aq) ----->   2H2O(l)  +  Na2SO4(aq)

using 10ml of the sodium hydroxide should mean that 5ml of sulphuric acid therefore it is dibasic as half the amount can neutralise and it produces 2h2o's to 1 h2so4.

you can also do (concetration of sodium * volume of sodium)/ (moles of sodium) = (concentration of sulhuric *vol of sulphuric)/ (moles)

(1*10)/2   =  (1*5)/1

5  =    5

therefore this proves it is dibasic

[Lil-lindz]

you need all the acid to react so you can compare the amount of gas given off for each acid, if it was the other way round you would find out gas given off for a certain amount of metal, or at least that is my understanding

Thank you, I understand now
Just one more question; in the titration would you place the H2SO4 or the base (NaOH) in the burette because I was always taught to place the substance you know the most about in the burette but I know the same amount about both substances so I don't know which substance to put where? Can anyone help?

Thanks

put the acid in the conical flask and the base in the burette this is what i found most effective as you need to wait for a colour change in the acid and it is easier to do it this way round as phenolphyalene (sorry if its spelt incorrectly) indicator turns from colourless to pink/purple which is a more obvious change than from pink/purple to colourless and so the results will be more accurate

[Borek]

phenolphthalein

[xxclarissaxx]

I have this problem for my coursework too. I know that by doing the titration you will find out that it takes half the amount of H2SO4 to neutralise the NaOH and this can be shown by the equation because the ratio of moles of acid to base is 1:2 but how do you show that this proves that H2SO4 is dibasic?

Any help is greatly appreciated 

[jazzy1331]

i am using this for the gas collection :

2HCl + Na2CO3 ->  CO2 + H20 + Na2Cl

H2SO4 + Na2CO3  ->  CO2 + H2O + Na2SO4

can  anyone help me because i do not know how much of each thing to use???

[Rob!]

Can anyone help with the dilution quantities? im guessing that to dilute H2S04 of 1.00 mol, you would transfer 25cm into a 250cm volumetric flask and then fill the rest with water which would then give you 0.1 mol?
Another question is - why do we have to dilute the acid? Also, do we have to dilute both the acid and the base?

[false_idols_fall]

Because reaching high up to pour 1M of NaOH or H2SO4 into a burette isn't the most sensible thing you could do.

[false_idols_fall]

I'm sure that anyone who doesn't do AS OCR chemistry is pretty confused as to what we are exactly supposed to do
so here's the question
"Sulphuric acid, H2SO4, is a dibasic (diprotic) acid. This means that one mole of sulphuric acid can release two moles of hydrogen ions, H+, when it reacts in aqueous solution.

Your are required to plan two different experiments that would enable you to prove that sulphuric acid is dibasic.

One of your experiments should involve a titration and the other should involve collection of a gas.

Your planning must be based on the assumption that your are provided with the following:

- aqueous sulphuric acid, of concentration 1.00mol dm-3
- any chemicals (other than sulhpuric acid) and equipment that you require from your school/college laboratory. "

It then goes on to say that you should draw diagrams, etc.
It then says you need to show a specimen calculation to show how the basicity of sulphuric acid would be worked out from the titration data. Could anyone describe how to do this? I have no idea what basicity means.

[kestrel5]

I know theres been quite a bit of help on the concentrations you need, but I just thought I'd point out that it doesn't give you 1 M of sulphuric acid, it gives you 1 mol dm-3. Does this matter? Will I still need to dilute it? I was always told by my chemistry teacher not to get moles and moles per dm cubed mixed up - but i never really knew the difference!

[Arkcon]

I know theres been quite a bit of help on the concentrations you need, but I just thought I'd point out that it doesn't give you 1 M of sulphuric acid, it gives you 1 mol dm-3. Does this matter? Will I still need to dilute it? I was always told by my chemistry teacher not to get moles and moles per dm cubed mixed up - but i never really knew the difference!

Can you convert the units?  What is the textbook definition of M, moles, and "dm-3"?

[moomin118]

looks like we're all stuck with the same planning exercise
I am given aqueous sulphuric acid, of concentration 1.00 mol dm^-3


for the titration, is there anything wrong with

H₂SO₄ + 2NaOH --> Na₂SO₄ + H₂O

im planning on using pthenolpthalein for indicator

i just dont see how it proves its dibasic. will the amount of NaOH just be double the amount of H₂SO₄? that seems ridiculously easy i must have it wrong 
i really dont want to do another titration with HCl and compare
i'd much rather list some calculations

lovely jubbly

what do you think?

[Arkcon]

i just dont see how it proves its dibasic. will the amount of NaOH just be double the amount of H₂SO₄? that seems ridiculously easy i must have it wrong 

It does sound easy, but how will you define the amount you'll be "doubling".  That may give you the whole answer.

[upsidedown]

Do I need do show how much hydrogen is realeased in the gas collection?
If so, how to i do it.


Will it be acceptable for me to do two gas collections one with HCl and one with H2SO4 to show that it is dibasic?

[chocoholic4lyf]

do you have to draw pH curves in the planning?