Chemistry

posted by .

For a chemistry lab the experiment was to carry out an acid-base titration to determine the exact concentration of a sodium hydroxide solution.

Two trials were completed and the data collected was: mass of weighing paper, mass of weighing paper + KHP, mass of KHP, initial buret reading, final buret reading, and volume of NaOH.

The molecular weight of KHP is 204.44 grams/mol.

I need to find the number of moles of KHP, the number of moles of NaOH and the concentration of NaOH but i am not sure how to do this. Please help,thank you!!


so for the moles of KHP it would be 1/204.44 = 0.00489 g/mol?

The volume of NaOH for trial 1 was 14.50 mL and for trial 2 it was 9.90mL. so for molesof NaOH would it be 39.998 which is the molecular weight og NaOH divided by the volume for each trial?

Then for the concentration of NaOH would i use the number of moles that I got and divide that by the volumes of NaOH?

Thank you for your help! I am not very good with this chemistry stuff.

  • Chemistry -

    It would have been better to have typed in the numbers. As it is I don't know if you are right or not but it appears you are on the right track on parts and not on the right track for parts.

    mass KHP = (mass KHP + mass paper)-mass paper.
    volume NaOH = final buret reading - initial buret reading.

    Here is the equation.
    KHP + NaOH ==> NaKP + H2O
    I have for the molar mass of KHP = 204.22.

    moles KHP = mass in grams KHP/204.22

    moles NaOH = the same since the equation shows 1 mol KHP = 1 mol NaOH

    M NaOH = moles NaOH/L NaOH
    You know moles NaOH from above and L NaOH (you show 0.00990L and 0.01450)
    Note:I think I answered this before but some of what I said must have been garbled. At any rate, it is important that you understand the concept of titration. You want to determine the M NaOH. So you use an acid that you can weigh exactly (KHP), then titrate with an indicator to the exact neutralization point. When you are there you know that moles NaOH exactly equal moles KHP. Then knowing moles NaOH and volume of NaOH you can calculate M NaOH. The KHP is called a primary standard because you can weigh a sample of 100% KHP and know the moles that are there. You CANNOT weigh NaOH and know the number of moles because NaOH absorbs water and CO2 from the air; thus, NaOH cannot be used as a primary standard. I hope this helps.

  • Chemistry -

    yes thank you i understand the parts for moles of KHP and NaOH. So the mw of KHP was given to me which was 204.44g/mol so for moles of KHP i did 1/204.44 and got 0.004 and then for NaOH i got 0.004 as well. Then for the concentration of NaOH would i do 0.004/0.0145 and 0.004/0.00990 ?

  • Chemistry -

    Why are you throwing perfectly good numbers away?. I assume the 1 you are using comes from 1.00 grams KHP. Then 1.00/204.44 = 0.004891 moles which you should round to the appropriate number of significant figures. But you apparently just threw away the 891.
    So (NaOH) = 0.004891/0.0145 and 0.004891/0.00990. I seem to remember you used 1.00 as grams which gives you three s.f. so the final answer should be rounded to 3 s.f.
    Your precision is not very good if this is for the same NaOH solution. For whatever it's worth a VERY GOOD analytical chemist can duplicate results to about 2 parts per thousand for an acid/base titration. In real numbers, if the actual value is 0.1000M, a chemist might get 0.0999M to 0.1001M

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Chemistry

    For a chemistry lab the experiment was to carry out an acid-base titration to determine the exact concentration of a sodium hydroxide solution. Two trials were completed and the data collected was: mass of weighing paper, mass of weighing …
  2. Chemistry(Please help!!)

    For a chemistry lab the experiment was to carry out an acid-base titration to determine the exact concentration of a sodium hydroxide solution. Two trials were completed and the data collected was: mass of weighing paper, mass of weighing …
  3. Chemistry(Please help, thank you!)

    For a chemistry lab the experiment was to carry out an acid-base titration to determine the exact concentration of a sodium hydroxide solution. Two trials were completed and the data collected was: mass of weighing paper, mass of weighing …
  4. chemistry

    a sodium hydroxide solution was prepared according to the procedure outlined in this weeks experiment. This sodium hydroxide solution was standardized by by titration against exactly 10mL of a 0.28M hydrochloric acid solution. In three …
  5. Chemistry - Science

    In an acid-base experiment at 25.0°C, a sodium hydroxide solution was standardized against KHP. The average value for the concentration of the sodium hydroxide solution was calculated to be 0.0125 M. This solution was used to titrate …
  6. College Chemistry - Science

    In an acid-base experiment at 25.0°C, a sodium hydroxide solution was standardized against KHP. The average value for the concentration of the sodium hydroxide solution was calculated to be 0.0125 M. This solution was used to titrate …
  7. Chemistry

    The concentration of a certain sodium hydroxide solution was determined by using the solution to titrate a sample of potassium hydrogen phthalate (abbreviated KHP). KHP is an acid with one acidic hydrogen and a molar mass of 204.22 …
  8. institute of health sciences

    Chemistry A) determine the mass of sodium hydroxide needed to prepare 100ml of 0.5M standard solution B) describe the procedure used to prepare the standard solution C) use the 100ml stock solution of 0.5M sodium hydroxide to neutralize …
  9. chemistry

    A domestic cleanser contains concentrated HCl as the active ingredient. A titration experiment was carried out to determine the concentration of HCl in the domestic cleanser. 20.0 ml of the cleanser were diluted to 250.0 ml with distilled …
  10. Chemistry

    a domestic cleaner contains concentrated hydrochloric acid as the active ingredient. a titration experiment was carried out to determine the concentration of hydrochloric acid in the domestic cleanser. 20.0mL of the cleanser were diluted …

More Similar Questions