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AS titration/standard solution help

im meant to make a standard solution thingie.. i have to use sodium carbonate and sulphuric acid... im not too sure where to start as i've just gotten back from 1/2 term - my brain isnt working right now + im generally extremely bad at chem!
thanks for any help!
Nat

Reply 1

shortornotnat

Na2CO3 - its meant to be between 0.05 and 0.15 mol dm -3. I think I will make a standard solution of 250cm3 with the concentration of 0.1 mol dm-3.

can anyone tell me if this is right? i would appreciate it a lot.

Na2CO3
rfm = 25 + 25 +12 + 16 + 16 + 16 = 106

250cm3 of 0.15 mol dm3-

mols = concentration x volume
= (0.1 x 250)/1000
= 0.025mols

grams = mols x rfm
= 0.025 x 106
= 2.65grams

so basically do i just weigh out 2.65g of sodium carbonate to make my standard solution?

Do I just put 25cm3 of the sodium carbonate into the conical flask for the titration or do I have to do another calculation?

sorry, but 1 more question... what type of information would i need to include in my plan? would it be information about acid base reactions, neutralisation, about the indicator? is there anything else that i must include?

It would be nice if someone could help before monday because thats when i have to do the actual experiment!
Thanks for any help,
Nat

Reply 2

Ghetto_Princess12

You have to measure the required amount, transfer the solid into the beaker add the solution and mix. Transfer the mixture into a stardard flask and fill the flask until it reaches the menicus level.

For the plan, you'll need to include details of the procedure used, and consider appreciation of scale and meaurement. Also you'll have to carry out a titration calculation and include any safety precaution you'll be using.

Reply 3

hai2410

is there any particular reason why everybody seem to do 250cm3 of standard solution (am i missing something here).
Also, when they say standard solution, what do they mean, because i thought a standard solution was just a solution of known concentration- but in order to find the concentration you've got to a titration don't you, and yet it seems in order to do a titration you've got to have a standard solution. :s-smilie:

thanks

Reply 4

ooze

Well it depends on what equipment your lab has. I remember the lab at my college only seemed to have 250ml volumetric flasks so that is what solution we had to make. You also need to make sure that it's going to be enough for a few titrations.

And in the titration you have two solutions and you need to know the concentration of one otherwise you wouldn't be able to find the concentration of the other. So you use a standard solution of known conc, or make one. To make a solution of known conc you use that moles = mass / rmm = conc x volume.

Reply 5

hai2410

Thank you. I've since realised what an idiot I am. making a standard solution is simple in theory, but perhaps a little tricky in practise and your average Volumetric Flask tends to be 250ml as well, i knew that, i was just being daft.

oh well.