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I am having real difficulties with buffers and titration calculations..

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  • I am having real difficulties with buffers and titration calculations..

    so can anyone recommend any good and useful textbooks and websites please! I am DESPERATE! I am a first year btw and would reeeeeealy appreciate the help. Thank You.

  • #2
    Re: I am having real difficulties with buffers and titration calculations..

    Hi shenzys

    The first thing I would suggest is to go over your A-level chemistry notes, as a lot of introductory stuff on buffers/titrations in the first year are pretty much a review of A-level chem.
    Have you tried Pharmaceutical Analysis by D G Watson ? It's a useful intro text to buffers - you might want to check it out.
    http://i620.photobucket.com/albums/t...snroses2-1.jpg

    ”We are real. We are not glam sh*t or anything else. We are Guns N’ Roses.”

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    • #3
      Re: I am having real difficulties with buffers and titration calculations..

      Must be over 50 yrs ago but I always understood buffers as a means of stabilising the splitting of molecules into active ions. Sodium citrate and borate being examples. Typically salts of weak acid and strong base or vice versa.
      johnep

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      • #4
        Re: I am having real difficulties with buffers and titration calculations..

        The Pharmaceutical Press have published some books and workbooks on pharmaceutical calculations. Details here

        http://www.pharmpress.com/9780853696032

        These books can be borrowed from the Society's library. The library is free to join for students doing an MPharm. Books are posted free, you can keep them for 28 days and renew once. Returning them is at your own cost.

        RPSGB.org: Using the library
        Gowan
        [email][email protected][/email]
        [url]www.pjonline.com[/url]

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        • #5
          Re: I am having real difficulties with buffers and titration calculations..

          ring some of your mates, meet up with them in computer room/library, and discuss things with them.

          a lot of students manage to get copies from the 2nd year students ' in your case' and follow the same pattern.

          i listed the easiest ways, but you can always do it your own way and read through a book ( trust me it will just waste your time! if you want to read, read something interesting like PJ and C+D.....)
          [COLOR=Olive]xxxx They tried to break my back, but i survived. whatever doesn't kill you, will only makes you stronger xxxx
          [/COLOR]

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          • #6
            Re: I am having real difficulties with buffers and titration calculations..

            Try getting A-level chemistry calculations by Ramsden....the whole book is dedicated to titrations, buffers, electrode potentials, pH calculations etc....i've got it and it helped me through the 4 years alot. I loved it so much, i've recommended it to others on amazon....got my copy for 3 pounds!!

            Lazy Lady...
            [IMG]http://www.polyvore.com/cgi/img-set?.out=jpg&id=VgnFNpwK3hGyUXFqqJvo3g&size=l[/IMG]

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            • #7
              Re: I am having real difficulties with buffers and titration calculations..

              I am stuck on questions like the ones below:

              q)A buffer was prepared by adding 0.25 M sodium hydroxide solution to
              200 mL of 0.2 M acetic acid solution until the pH was 4.6. Calculate the
              volume of sodium hydroxide solution required.
              Acetic acid (CH3COOH), pKa = 4.76

              q)The BP requires ferrous fumarate in capsules to contain not more than 1%
              ferric iron.
              The contents of 20 Ferrous Fumarate Capsules were emptied and
              1.5362 g of the powder used to determine the ferric iron content. The
              powder was dissolved in hydrochloric acid and then 3 g of potassium
              iodide added. The liberated iodine was titrated with 0.0503 M sodium
              thiosulphate and 6.17 mL required. Given that each mL of 0.05 M sodium
              thiosulphate is equivalent to 2.792 mg Fe(III), calculate the ferric iron
              content (% m/m) of the powder. Do the capsules meet the BP
              requirement?

              I read the nots I am given and ry to attempt these but I am getting nowhere!!! I cried today and I'm guessing that won't be the last time these ****** calculations get to me! ARGH!
              Can anyone do these? If yes, is there a technique/ standard set frmuals I can learn to do them too?

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              • #8
                Re: I am having real difficulties with buffers and titration calculations..

                This may help you. For the first question you can either find a formula that connects pH and pKa or you can calculate it by calculating Hydrogen ion concentrations.

                For the second question calculate the amount of Fe3+ (hint each Ml=2.xxx and you are given the amount) This is in 1.5362g so percent is Fe3+/1.5xxg. The question here is not testing your understand so much but trying to develop your information handling skills, something that will be essential in your career. However be careful with the units mg and g.

                A tip for exams and this type of question is to underline important terms and information and then to ask yourself what are they really asking.
                Real stupidity beats artificial intelligence every time.
                (T. Pratchett)

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