Question

Based off info below please answer blank boxes. Thanks! Application Questions: 12. Before using a solution...

Based off info below please answer blank boxes. Thanks!

Application Questions:

12. Before using a solution of NaOH as a standard for a titration, its precise concentration must be determined by titration with a standard acid. This is because solid NaOH absorbs water from the atmosphere, so its solid form is difficult to keep free of contaminated H2O. A common acid used for standardization is the acid-salt, potassium hydrogen phthalate (KHP), KHC8H4O4. Another way is to use a standardized solution of sulfuric acid:

H2SO4(aq)   +   2NaOH(aq)       ®      2H2O(l)   +   Na2SO4(aq)

If 16.27 mL of 0.1125 M H2SO4 is required to titrate a 20.00 mL solution of NaOH, what is the molar concentration of the NaOH solution? Show your work.

    
  

13. A student wanted to know the mass of vitamin C (ascorbic acid) in a vitamin C tablet. She dissolved the tablet in water and then titrated with 0.200 M NaOH. The balanced equation for the acid-base neutralization reaction is:

HC6H7O6(aq)   +   NaOH(aq)       ®      H2O(l)   +   NaC6H7O6(aq)

If 24.41 mL of NaOH was required to reach the endpoint, how many moles of ascorbic acid are in the tablet?You don’t need to show your work here.

  
  

What is the mass of ascorbic acid in the tablet?(MM = 176.12 g/mol)

  
  

Given that the student measured the mass of the vitamin C tablet as 4.601 g, calculate the percent-by-mass of ascorbic acid in the tablet.


  

  
  





Homework Answers

Answer #1

The reactiion is

2NaOH+ H2SO4----> Na2SO4+ 2H2O

It suggersts that two moles of NaOH is requuried to react with 1 mole sof H2SO4.

Moles of H2SO4= Molairty * Volume of H2SO4= (16.27/1000)*0.1125 =0.00183 moles

Hence,. moles of NaOH reqiored = 0.00183*2 = 0.003661

From moles= Molarity* Volume

0.003661 =Molarity* (20/1000)

Molairty =0.003661*1000/20=1.833305M

b)

as per the reaction, one mole of NaOH is required to neutralize 1 moles of Ascorbic acid

Moalirt of NaOH =0.2M

Volume consumed =24.41ml=24.41/1000 liters =0.02441liters

Moles of NaoH =0.2*0.02441=0.004882 gmoles

Hence, moles of ascorbic acid in the tablet = 0.004882 gmoles

Molecular weight of Ascorbic acid ( HC6H7O6) =1+ 6*12+1*7+6*16= 176

Moles = mass/ molecular weight=

Mass of ascorbic acid =Moles* Molecular weight =0.004882 *176 =0.8592 gms

Mas of the vitamin C = 4.601 gms

Mass % of ascorbic acid = (mas of ascorbic acid/ mass of vitamin)*100 =(0.8592/4.601)*100=18.67%

Know the answer?
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Not the answer you're looking for?
Ask your own homework help question
Similar Questions
In Part 1 of Lab 2 you will make and standardize a solution of NaOH(aq). Suppose...
In Part 1 of Lab 2 you will make and standardize a solution of NaOH(aq). Suppose in the lab you measure the solid NaOH and dissolve it into 100.0 mL of water. You then measure 0.2013 g of KHP (KC8H5O4, 204.22 g/mol) and place it in a clean, dry 100-mL beaker, and then dissolve the KHP in about 25 mL of water and add a couple of drops of phenolphthalein indicator. You titrate this with your NaOH(aq) solution and find...
Below is the background info for the lab assignment. The 4 blank boxes are the questions...
Below is the background info for the lab assignment. The 4 blank boxes are the questions I would like answers too. The end point for the fine titration was 35.90 mL in the burette when the solution turned bright green again. And the coarse titration I got 35.36mL as the end point. 35.9 mL is exact in case you need that info. Thanks! Background In this lab, we will determine the amount of alcohol (ethanol), C2H5OH, in a commercial vodka...
Water Hardness Lab follow up Questions Trial Initial EDTA Volume (mL) Final EDTA Volume (mL) Total...
Water Hardness Lab follow up Questions Trial Initial EDTA Volume (mL) Final EDTA Volume (mL) Total Volume of EDTA Used (mL) 1 8.5 6 2.5 2 5.0 3.0 2.0 3 3.0 0.5 2.3 Average Volume of EDTA Used (mL): 2.3 Average Volume of EDTA Used (mL) Concentration Ca2+ Ions Per Liter of Water (mol/L) Water Hardness (ppm CaCO3) 2.3 0.0023 230 2.Approximately how much calcium would you ingest by drinking six, 8-oz glasses of your local water? Hint: 1 oz...
What are standard conditions of ΔH° for the data you will use? Temperature 0 K 100...
What are standard conditions of ΔH° for the data you will use? Temperature 0 K 100 K 273 K 298 K Pressure 1.0 Pa 100 Pa 1.0 bar 100 bar Concentration 1.0 g/L 1.0 mol/L 1.0 mg/L mol/kg Select the complete reactions (including phases) for the reaction between solid NaOH and a solution of HCl. 2NaOH(s) + HCl(aq) → 2NaCl(aq) + H2O(l) NaOH(s) + HCl(aq) → NaCl(aq) + H2O(l) NaOH(s) + HCl(aq) → NaCl(s) + H2O(l) Calculate the theoretical ΔH°r...
ADVERTISEMENT
Need Online Homework Help?

Get Answers For Free
Most questions answered within 1 hours.

Ask a Question
ADVERTISEMENT