This discussion is closed.
cold_blood
Badges:
#1
Report 16 years ago
#1
we are just about to do our chemistry coursework and i have to plan a method to find out the relative molecular mass of an acid. i know that it includes titration but dont know how to do the maths at the end, especially because i have to decide the molarity of NaOH to use and the mass of acid to use. Anyone have any ideas?
the acid is COOH(CH2)nHOOC where n is between 1 and 4 and its diprotic (i know this changes what i have to do but am not sure how)
the alkali is NaOH
the equation, putting acid as H2A:
H2A + 2NaOH > Na2A + 2H2O
i have to 'decide on a scale for the experiments', what does that mean?
0
chrisbphd
Badges: 2
Rep:
?
#2
Report 16 years ago
#2
(Original post by cold_blood)
we are just about to do our chemistry coursework and i have to plan a method to find out the relative molecular mass of an acid. i know that it includes titration but dont know how to do the maths at the end, especially because i have to decide the molarity of NaOH to use and the mass of acid to use. Anyone have any ideas?
the acid is COOH(CH2)nHOOC where n is between 1 and 4 and its diprotic (i know this changes what i have to do but am not sure how)
the alkali is NaOH
the equation, putting acid as H2A:
H2A + 2NaOH > Na2A + 2H2O
i have to 'decide on a scale for the experiments', what does that mean?
The scale of the experiments means things such as what volumes and concentrations of acid and alkali you would use. You need to explain why you choose each one. Consider things such as the size of the equipment, make some preliminary calculations to see how much of a randomly chosen concentration of acid is needed to neutralise a certain volume of standard acid. Also think about safety (you dont want concentrations that are too high). Decide on an indicator to use (you are doing a weak acid-strong base titration so look one up in a book).

I did this exact coursework when I did my A Levels, and it is really easy so long as you work methodically through it. You should get a sheet that has numbered points on it for you to cover - this really helps.

Good Luck
0
Ben.S.
Badges: 2
Rep:
?
#3
Report 16 years ago
#3
Phenolphthalein ought to do it.

Ben
0
chrisbphd
Badges: 2
Rep:
?
#4
Report 16 years ago
#4
It should. I couldn't remember - it is module 5!
0
X
new posts
Back
to top
Latest
My Feed

See more of what you like on
The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

Personalise

If you do not get the A-level grades you want this summer, what is your likely next step?

Take autumn exams (125)
46.99%
Take exams next summer (37)
13.91%
Change uni choice through clearing (68)
25.56%
Apply to uni next year instead (24)
9.02%
I'm not applying to university (12)
4.51%

Watched Threads

View All