Students must calculate grams for each of these 8 buffers: 1. 100mL of 0.50M sod
ID: 474801 • Letter: S
Question
Students must calculate grams for each of these 8 buffers:
1. 100mL of 0.50M sodium phosphate buffer, pH 7.0
2. One liter of 0.050 M sodium phosphate, pH 7.0
3. One liter of 0.15M sodium phosphate, pH 6.2
4. 250mL of 0.050M sodium phosphate, pH 7.0 with 0.050M NaCl.
5. 250mL of 0.050M sodium phosphate, pH 7.0 with 0.150M NaCl.
6. 250mL of 0.050M sodium phosphate, pH 7.0 with 1.0M NaCl
7. 250mL of 0.050M HEPES, pH 7.8. Also calculate the volume of 2M KOH required.
8. 250mL of 0.050M Tris-HCl, pH 8.8. Calculate the volume of 2M HCl required.
I'm guessing you need to calculate the grams of each the conjugate base and the acid. (Using Henderson Hasselbalch).
st of Some com mori onoB Ca ACID ACETIC ACID ASCORBIC ACID CARBONIC ACID PIPES Phosphoric Acid HEPES TRIS pKa 4.76 4.15 6.10 10.3 (a diprotic acid, hence 2 pKa values) 6.80 2.14 6.80 12.3 (a triprotic acid, 3 pKa values) 7.60 8.30 22Explanation / Answer
Weight of sodium buffer= molarity*molecular weight *Volume
(1) 100 ml of 0.5 M sodium phosphate buffer
Sodium phosphate molecular weight = 141.96 gm/mol
gm= 0.5 mol/lit * 100*10-3 lit *141.96 gm/mol =7.098 gm
(2) 1 lit of 0.05 M sodium phosphate
gm= 1*0.05*141.96 = 7.098 gm
(3) 1 lit of 0.15 M sodium phosphate
gm= 1* 0.15*141.96=21.294 gm