[spy derman]

i need some help with a bit of work, in how to prove h2so4 is dibasic by a gas collection method. this is for my colledge and i need to get it done beacause it's due in on monday

[spy derman]

anyone? i need to know for the gas collection method how im gonna prove its dibasic. what mass of mg to use and so on

[spy derman]

so no one is gonna help me?

[enahs]

Somebody sure is inpatient. A whole 30 minutes without an answer.

A little thought and effort with this question will go a long way.
Google: prove H2SO4 is dibasic will also help a lot.

[spy derman]

i just need a little help with the gas collection method
im using mg as the metal that reacts with h2so4 and hcl
i think h2so4 will produce double the volume of gas than hcl would
am i right?

[enahs]

You tell me. Write out the balanced equations for the reaction of:

Mg + HCl ->   ? + ?
and
Mg + H2SO4 -> ? + ?

And so for equal volumes and concentrations; which one produces more?

[spy derman]

mg + 2hcl--> mgcl2 + H2
mg + h2so4 --> mgs04 + H2

the concentration for both is 1moldm3 and i've decided to use 10cm3 volume
if i work out the moles for each i get 0.01mol for h2so4 and that produces 240cm3 of h2 gas because ratio of h2s04 to h2 is 1:1
for hcl at 0.01mol it produces 120cm3 of h2 gas because ratio of hcl to h2 is 2:1

am i right here? i need to prove how its dibasic now

[spy derman]

also is the mass of magnesium used going to be the same for both HCL and h2so4 experiment?

[Borek]

First of all: we have at least two threads in which these things were discussed to death, you have found these threads, but looks like you have not tried to read them. For example calculation of Mg amount was done there, yet you ask the same question. Reread information there and ask your questions later.

i need to get it done beacause it's due in on monday

Since when do you know about it?

[spy derman]

First of all: we have at least two threads in which these things were discussed to death, you have found these threads, but looks like you have not tried to read them. For example calculation of Mg amount was done there, yet you ask the same question. Reread information there and ask your questions later.

i need to get it done beacause it's due in on monday

i've read it but still dont understand how i would say h2so4 is dibasic. plus i need to know if i the mass of magnesium used for both experiments is the same
Since when do you know about it?

huh?

[spy derman]

anyone care to help?

[Borek]

Amount of magnesium needed is a function of amount of acid that you expect to find on your sample. If you are not sure whether the acid is mono- or diprotic, you better use safe excess of Mg, aiming at the worst case scenario.

[spy derman]

Amount of magnesium needed is a function of amount of acid that you expect to find on your sample. If you are not sure whether the acid is mono- or diprotic, you better use safe excess of Mg, aiming at the worst case scenario.

i dont understand
i used 10cm3 of h2so4 and found the moles to be 0.01mol
do i find the mass of mg needing to be used by doing mass=moles x molar mass
that would give me 0.243grams that would be required to react with h2so4.or do i use excess mass like 0.5grams
also would this mass of magnesium be used for the reaction with HCL?

[spy derman]

well? how will i fid out how much magnesium to use

[Mr. Brightside]

Listen mate, simply put, go for an excess.

I'm using 25.00ml 0.1mol acid with excess Mg. to equal it, it should be 2.43 grams (i think, sorry, but i'm really tired). Go for an excess of say... 5 grams, then you shouldn't have much problem....

Let me know if i'm wrong, this is something that i'm not excellent at in all honesty.

pm me if you wanna discuss more... will try to be of help (Y)