1.You need to make 1 L of 0.1M HEPES (pKa 7.55) at pH 8.0. You have...
In this lab, you prepared a buffer and then determined its pH, but in a laboratory setting it is usually the other way around – you need a buffer at a particular pH, and this dictates its preparation. Describe how you would prepare 500. mL of 0.1500M HEPES at pH = 7.80, given appropriate glassware, HEPES (mw = 238.3g/mol, pKa = 7.48) and HEPES sodium salt (mw = 260.3 g/mol) at 25°C. Your answer should include all relevant calculations. (Note:...
1.- Part I: You have a 1 L 0.1M phosphate buffer solution at pH 6.8. To this you added 10 mL of 6M HCl. What is the resulting pH of this solution? (pKa values for phosphoric acid are: 2.2, 6,8 and 12.4) Part II: If you had pure phosphoric acid then added to this 1 molar equivalent of KOH, what would the resulting approximate pH of this solution be and what form or forms of phosphoric acid would you predict...
3. Describe, quantitatively, how you would make 250 mL of a 40 mM HEPES buffer at pH 7.60. You have access to HEPES sodium salt (molar mass = 260.29), unlimited 1 M NaOH and unlimited 1 M HCl.
Not sure how to go about this problem, help please
2.) You need to make a buffer to use in the first step of the purification. You determine that a 0.1M buffer at a pH of 7.40 would be ideal. You choose one of the Good Buffers in the table shown below: Buffer MW pKa (20°C) Apka/ °C HEPES, free acid 238.3 7.55 -0.014 MOPS, free acid 209. 3 7.20 -0.006 Tris base 121.1 8.30 -0.031 MES, free acid 195.2...
A.Can you show me how to make a 0.1M 250mL buffer solution by 18M H3PO4 (pka = 2.16) and 0.103M NaOH? The assigned pH is 2.60. I need the calculation: how many mol of H3PO4 and NaOH needed? How many ml? in 250mL solution. B.How much 0.1M NaOH should have been required in order to increase the pH of a 25.00 mL sample of your buffer to the pKa + 1 limit. C.How much 0.1M HCl should have been required...
Maleic acid contains two carboxylic acid groups, one with a pka
of 2.0 and a second with a pKa of 4.0. The fully protonated from of
malice acid is shown on below. Briefly describe how you would
prepare 0.25L of a 0.1 M buffer at pH = 2.0, assuming that you are
starting with the disodium salt of the acid. You should give the
moles of sodium malate (MW 178.05 g/mol ) and HCL (36.46 g/mol)
that you would need...
Question 4. a.) Calculate the pH of a solution initially 0.1 M in acetic acid and 0.02 M in sodium acetate. The pKa for acetic acid is 4.76. b) Calculate the pH of the buffer if you add 10 ml of 0.1M HCl to 100 ml of the buffer in part a.
If in lab you need to make a buffor pH =10 using 0.1M NH3 & 0.1M NHgCl, how many ml of each would you need to make the buffer?
Suppose you want to make 500 mL of a 0.20 M Tris buffer at pH 8.0. On the shelf in lab, you spot a bottle of 1.0 M Tris at pH 6.8 and realize you can start with that to make this new buffer. Assuming you have 5.0 M HCl and 5.0 M NaOH at your disposal, how could you make this 0.20 M Tris buffer at pH 8.0 from the 1.0 M Tris, pH 6.8? (The pKa of Tris...
1) Suppose you have 50ml of a 0.1M acetate buffer with a pH of 4.37 and a pka of 4.73 which has been treated with 2.4 ml of 0.5M Sodium Hydroxide (NaOH). Calculate the theoretical change in pH following the addition of this base.