[Arkcon]

 

[chocoholic4lyf]

just a yes or no would do

[moomin118]

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.

the whole answer
i like the sound of that haha

so if H2SO4 and NaOH are both at 1mol/dm concentration
NaOH should be double the amount of H2SO4 to neutralise


but how does that prove that H2SO4 is dibasic?

because... there are two H+ for every OH-?

[Arkcon]

so if H2SO4 and NaOH are both at 1mol/dm concentration
NaOH should be double the amount of H2SO4 to neutralise


but how does that prove that H2SO4 is dibasic?

because... there are two H+ for every OH-?

... theoretically, if you have a 1 M HCl and a 1 M NaOH solution, how man H+ per OH would you have? 

[moomin118]

so if H2SO4 and NaOH are both at 1mol/dm concentration
NaOH should be double the amount of H2SO4 to neutralise


but how does that prove that H2SO4 is dibasic?

because... there are two H+ for every OH-?

... theoretically, if you have a 1 M HCl and a 1 M NaOH solution, how man H+ per OH would you have? 

if it was HCl there would be 1:1
so it should be the same amount of HCl and NaOH to neutralise


will it be enough to say that because 1 mole of H2SO4 reacts with 2 moles of NaOH, it shows its dibasic or would another titration with HCl be necessary?

[Borek]

No need for another titration, although theoretical discussion will be nice.

[moomin118]

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!

a "mole" is a number, like a dozen

if i say i'll give you a dozen marbles im giving you exactly 12

1 mol dm-3 is the same as saying one mole per decimetre cubed
its a concentration

so in 1 dm3 there is 1 mole, in a 1 mol-dm3 solution

and in 1 dm3 there is 2 moles, in a 2 mol-dm3 solution

[moomin118]

No need for another titration, although theoretical discussion will be nice.

ok thankyou, one other thing

in the gas collection experiment
is there a special name for the bung that goes in a conical flask with a hole in the middle and the tube? (that the Hydrogen will travel through)
 

[whoooosh]

stumbled across this page and its full of pretty good stuff 

in regards to the calculations
on other titrations i have done
you find out how much of the base was needed to neutralise the H2SO4
then you have to multiply this by the conc, which is 1.00
this will give you the amount of moles of base you used
then write a balanced equation of the reaction
to see how many moles of H2SO4 are being used
then use this to work out the Mr
which should show you it is dibasic

hope i wrote it out correctly

[rosipose]

heyho

i dont know whether you guys have taken this into account but make sure you dilute both the H2SO4 and the NAOH in the titration otherwise you wont get any marks for safety...i would dilute both to 0.1moldm3, then the numbers are easier to work with when you multiply back up later on. (and add the water slowly to the sulphuric acid, in case you didnt already know)

for those of you who are reacting with hcl aswell- no need. in the gas experiment if you use a known amount of H2SO4 and react it with excess metal (i would use Mg ribbon) and collect the gas (H2) you can calculate very easily the number of moles hydrogen released per mole of sulphuric acid.

also with the gas experiment mention the use of an ignition tube to make sure all gas is collected..
for the titration, pretty much the same thing. titrate with NAOH at the same conc as the acid (0.1) and record volumes etc. make sure your results are concordant obviously then use the RAM of both substances to calculate ratio of moles and whatever...


and earlier on in the thread with the "doesnt prove its diprotic just proves H+ ions are released" or something similar-- that is irrelevant at the level this plan is. the exam board doesnt think we have the capacity to understand that yet. i dont think


and the bung with the hole in doesnt really have a name. just make up something complicated like "bung with delivery tube attachment". i reckon.

hope that helped...

[chocoholic4lyf]

how do i start the actual plan off?

[moomin118]

ive started mine off with an aim
something like, "to show that h2so4 is dibasic by using two different experiments"
then have a heading saying experiment 1 and off you go describing it

[chocoholic4lyf]

thanks

[sullivan_higgins]

Can someone please help me with figuring out the following...

- how to work out the ammount of HCL & H2SO4 needed in the gas collecting experiment.
- How to work out how much Mg is needed in the gas experiment, and how much is excess.

Thanks, and thanks for this thread.
helped so much 

[Borek]

Start with balanced reaction equations. This is simple stoichiometry. You want such a volume of gas to be produced, that it will be easy to measure. Then, you want to use slight excess of Mg to be sure, that all acid reacted.