Uber help needed in chemistry

[dpt90]

honestly i just need sumone to do my homework cause the teacher never explaind this stuff to me.. sry if these kinds of posts arent allowed...

   
Abstract:
 
The acetic acid[CH3CHOOH or Ethanoic acid] contentof commercial vinegar was discovered by using the method of titration.
 
Introduction:
 
Aim:
 
To find the acetic acidc content in a commercial vinegar.
 
Hypothesis:
 
When we add the correct ratio of dilute vinegar to sodium hydroxide(with indicator) it will neutralize and change from a dark pink to colorless but it will have a very light shade of pink. This is because phenolphthalien is pink in base substances and colorless in neutral substances.
 
Materials:

   1.      Hrdrometer (1-1.5 range) or balance
   2.      Vinegar (40mL)
   3.      Volumetric Flask (250mL
   4.      Wash Bottle
   5.      Conical Flask (250mL)
   6.      Pippettes(20mL and 25 mL)
   7.      Burette and stand
   8.      Funnel
   9.      Beakers (2x100mL)
  10.      Standard Sodium Hydroxide solution [NaOH] approximately 0.1 mol L (150mL)
  11.      Phenolphthalien (3 drops]

Method:

   1.      Determine the density of th vinegar by weighing out a known volume delivered from a pipette or by using a hydrometre.
   2.      Using a pipette place 25.0 mL of vinegar into a 250mL volumetric flask. Make the volume to precisely 250mL with distilled water. Mix well by repeatedly inverting the volumetric flask.
   3.      Titrate the diluted vinegar from a beurette against 20mL portions of standard NaOH solution each with 2-3 drops of phenolphthalein indicator. Record your results as before.
   4.      Keep adding the dilute vinegar until you notice a stark change in the color of the solution. Record how much dilute vinegar was added and.

Results: Test           InitialReading           Final reading         Volume of titrant 
             Test one     0 mL                       29.8 mL               29.8 mL 
             Test two      0 mL                      29.6 mL                29.6 mL 
             Test three    0 mL                     30 mL                   30 mL 
           Average 29.8 mL 


Discussion:
 
Notes – the molarity of the sodium hydroxide is, 0.1 mol Lˉ¹

   1. Calculate the number of moles of NaOH in 20 mL samples used.
   2. Write the equation for the reaction of acetic acid with sodium hydroxide and calculate the average no. of moles of acetic acid used in the titrations.
   3. Calculate the concentration of acetic acid in the dilute vinegar
   4. determine the concentration of acetic acid in the undiluted vinegar
   5. Calculate the mass of acetic acid in 1000mL of undiluted vinegar
   6. Use the density of vinegar to calculate the mass of 1000mL of vinegar
   7. Determine the mass of acetic per 100g of vinegar, that is, the percentage by mass of the acetic acid in the vinegar.
   8. What Volume of the undilute vinegar would be required in a titration with 20 mL of 0.1 mol Lˉ¹ NaOH solution, using phenolphthalein as indicator?
   9. Suppose that methyl orange, which changes color at pH 3.7, had been used instead of phenolphthalein in your experiment. Would you expect the calculated percentage of acetic acid to be too high or too low? Explain.

[ceyfer]

Wow I have done this before wayback in high school days but u must have a reference for this one

ur professor was lazy! u need to have the equipments and test it empirically- honestly I hate chemistry

this was my references before try to visit :)

http://library.thinkquest.org/3659/acidbase/
http://library.thinkquest.org/3659/

http://www.ipl.org/div/subject/browse/sci06.00.00/
http://library.duke.edu/research/sub...des/chemistry/
http://cds.dl.ac.uk/cds/other_info_a...s/cheminf.html

[Lenogris]

umm im thinking u should read the notes carefully do a little math all the answers are there just needs some thinking

[mEtRiX]

Sorry, never understood Chemistry properly. I just suck at it...

[Solaris]

Ok, I can help you with this, this is any easy investigation. It will be help me more, if you specify that what do you need. Calculations, or you want to understand the theory that works in the investigation or Both?

[Raymond]

I "nearly" flunk my chemistry :P

[ahashmi06]

Man chemistry sucks...

[blackrose]

I had done this in my school, now I think I am a dumb. As far as I know there is some kind of formula that will help you to calculate the needed stuff. Sorry I forgot that stupid formula. all you need is to use the mole concept.

http://www.launc.tased.edu.au/online...y/molemass.htm

http://en.wikipedia.org/wiki/Acetic_acid

http://answers.yahoo.com/question/in...6142157AAxG6Du (liked this one)

[yao90]

moles = mass/molecular weight
density = mass/volume
CH3COOH + NaOH ---> CH3COONa + H2O
Phenolphtalein changes into a pinkish color when pH is at 8.2-12, it is colorless if the pH is at 0-8.2.
pH=14-pOH
pOH=-log[concentration of OH] and pH=-log[concentration of H]
That's all information that I can remember. Can't help you in others. :D

[tangomouse]

Whats chemistry :D