# Based on question 1 how many moles of naoh were added

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Chapter 13 / Exercise 1
Mathematical Practices, Mathematics for Teachers: Activities, Models, and Real-Life Examples
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3.Based on question 1. How many moles, of NaOH were added when: a.pH = pKa1b.pH = pKa24.One source in the literature quotes 0.54 g/L as being the concentration of phosphoric acid, H3PO4, in Cola. What is it in molarity? Show your calculations and include units.
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Chapter 13 / Exercise 1
Mathematical Practices, Mathematics for Teachers: Activities, Models, and Real-Life Examples
Larson Expert Verified
Report sheet Exp. 8 Phosphoric Acid in ColaName:____________________ Date:____________ Lab Section:________________ Partner’s name:_____________ 1. Use your printed graph and data table to confirm the volume of NaOH titrant you recorded beforeand afterthe large increase in pH values upon the addition of 0.5 mL of NaOH solution. (Remember to include your graphs with the report sheets) 2. Determine the volume of NaOH added at each equivalence point. To do this, add the two NaOH values determined above and divide by two. 3. Calculate the number of moles of NaOH used. 4. See the equation for the neutralization reaction given in the introduction. Determine the number of moles of H3PO4reacted. 5. Recall that you pipeted out 40.0 mL of the beverage for the titration. Calculate the H3POconcentration. 46. pH = PKaat the half equivalence point. From pKayou can determine KaFirst Equivalence point Trial 1 Trial 2 Concentration of NaOH (M) Volume of Cola (mL) NaOH volume added immediately beforethe large pH increase for the first equivalent (mL) NaOH volume added immediately afterthe large pH increase for the first equivalent (mL) Volume of NaOH at the first equivalence point (mL) Moles of NaOH at first equivalence point (mol) Moles of Phosphoric acid from first equivalence point (mol) Volume of NaOH at ½ equivalence point (mL) pH (pKa1) at ½ first equivalence point Ka1Concentration of Phosphoric acid in Cola (M) From first equivalence point
Report sheet Exp. 8 Phosphoric Acid in ColaName:____________________ Date:____________ Lab Section:________________ Partner’s name:_____________ 1.Look up the values for the Ka for Phosphoric acid. List them here: Ka1__________ Ka2__________ Ka3__________ Second Equivalence Point Trial 1 Trial 2 Concentration of NaOH (M) Volume of Cola (mL) NaOH volume added immediately beforethe large pH increase for the second equivalent (mL) NaOH volume added immediately afterthe large pH increase for thesecond equivalent (mL) Volume of NaOH at the second equivalence point (mL) Moles of NaOH at second equivalence point (mol) Moles of Phosphoric acid from second equivalence point (mol) Volume of NaOH at 1½ equivalence point (mL) pH (pKa2) at 1½ first equivalence point Ka2Concentration of Phosphoric acid in Cola (M) From second equivalence point Average Concentration of Phosphoric Acid (M)
Report sheet Exp. 8 Phosphoric Acid in ColaName:____________________ Date:____________ Lab Section:________________ Partner’s name:_____________ 2.What are the percent errors for your values of Ka1and Ka2%Error Ka1__________ %Error Ka2__________ 3.If your percent error is greater than 10%, explain what would contribute to such a large percent error. If you had less than 10% error, Explain what techniques you employed to obtain such a small error. 4.A carbonated beverage maker claims that none of their colas contain more than 30 mg of phosphorus per 6-oz serving. Calculate the mg of phosphorous in a 6 – oz serving of cola, according to your experimental data. 1 fl. Oz = 29.5735 mL 5.Explain why the cola that you used in this experiment has to be “flat” with all the carbonation removed. What would happen if the cola was not flat? ?
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