/courses/13347/quizzes/38261/take In the lab exercise step 2a, you are asked to
ID: 715940 • Letter: #
Question
/courses/13347/quizzes/38261/take In the lab exercise step 2a, you are asked to prepare 100 mL of a sodium phosphate buffer of a pH and concentration that you choose, using 0.10 M NaH2PO4 and 0.10 M Na2HPO4. Calculate the amount (volume) of each reagent that is needed to make this buffer. What pH value will you chose to make? What concentration will you chose to make? What volume of NaH2POs will you use? mL What volume of Na2HPO4 will you use? mL What volume of water will you use? mL No at 10:29am Submit Quiz MacBook AirExplanation / Answer
0.1 M sodium phosphate 1 liter
Na2HPO4*2H20 (Molar mass = 178.05) 17.80 gm
NaH2PO4*2H20 (Molar mass = 138.07) 13.80 gm
To prepare 0.1 M sodium phosphate buffer
1. Dissolve 17.8 g of Na2HPO4•2H2O and 13.80 g of NaH2PO4•H2O separately in H2O.
2. Adjust the volume of each solution to 100 mL.
To prepare the buffer, mix the stock solutions as follows: at PH =7.2
For 100 mL: 36 mL of Na2HPO4•2H2O and 14 mL of NaH2PO4•H2O.
Volume of water = [100 - (36+14)] ml = 50 mL
ans:
a) PH = 7.2
b) 0.1 M
c) 36mL
d) 14mL
e) 50mL
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.