Number of results: 47
What is pH buffer of 0.1 mol L-1 Na2HPO4/O.15 mol L-1 KH2PO4? KH2PO4? Given Ka(H2PO4-) = 6.2 x 10-8). I would like to know the correct formula, steps for the answer Thank you
October 20, 2010 by Helen
This question pertaining to buffer systems! How would you prepare 10.0mL of 0.0100M phosphate buffer, pH = 7.4 0, from stock solution of 0.100M KH2PO4 and 0.250M K2HPO4, pKa of KH2PO4 is 7.20. Please help me in figuring out how I even start this problem...as well as attempting...
August 3, 2016 by Katie
Suppose you have to prepare 1.00 L of the solution ( KH2PO4 and Na2HPO4 pH=7.31) and that this solution must be isotonic with blood (have the same osmotic pressure as blood). What mass of KH2PO4 would you use?
March 16, 2013 by Pepz
A 10.00-mL sample of 0.1000 M KH2PO4 was titrated with 0.1000 M HCl Ka for phosphoric acid (H3PO4): Ka1= 7.50x10-3 ; Ka2=6.20x10-8 ; Ka3= 4.20x10-10 Calculate the pH after addition of 10.00 mL of HCl to the KH2PO4 solution?
August 7, 2014 by Jesus
As a technician in a large pharmaceutical research firm, you need to produce 200.mL of 1.00 M a phosphate buffer solution of pH = 7.19. The pKa of H2PO4− is 7.21. You have 2.00 L of 1.00 M KH2PO4 solution and 1.50 L of 1.00 M K2HPO4 solution, as well as a carboy of pure ...
September 14, 2013 by moses
As a technician in a large pharmaceutical research firm, you need to produce 100.mL of 1.00 M a phosphate buffer solution of pH = 7.45. The pKa of H2PO4− is 7.21. You have 2.00 L of 1.00 M KH2PO4 solution and 1.50 L of 1.00 M K2HPO4 solution, as well as a carboy of pure ...
March 31, 2014 by Billy Bob Reynolds
if 4 volumes of 0.1M monobasic potassium phosphate, KH2PO4, are mixed with 2 volume of 0.1 M dibasic sodium phosphate, Na2HPO4, what will be the pH of the mixture? What if 4 volumes of 0.1 M KH2PO4 are mixed with 8 volumes of 0.1 M ethanolamine base(pka=9.44) what will be pH ...
January 21, 2011 by dIrk
Calculate [H+] in 0.375M H2PO4 Ka=6.2x10^-8 I know I'm suppose to write the equation first, but I'm not sure if I did it right: H2PO4 + H2O <=> 2H+ + PO4 is that right? You need to clarify the question. Is that a salt, such as KH2PO4, that is 0.375 M or is it the ion ...
May 29, 2007 by Amanda
You need to prepare 1.000 L (in a volumetric flask) of 0.50 M phosphate buffer, pH 6.77. Use the Henderson Hasselbalch equation with a value of 6.64 for pK2 to calculate the quantities of K2HPO4 and KH2PO4 you need to add to the flask. What concentrations of [K2HPO4] and [...
October 20, 2010 by Anonymous
I posted a question earlier that I was having trouble with, but I was unable to attempt to try it again for several days after posting. The question was: A buffer is made up of .300 L each of .500 M KH2PO4 and .317 M K2HPO4. Assuming tha the volumes are additive, calculate a) ...
May 5, 2007 by James
A phosphate buffer solution contain 0.08 M K2HPO4 and 0.12 M KH2PO4. pKa values for H3PO4 are 2, 6.8, and 12.2. Calculate the concentrations of a) H3PO4 b) H2PO4- c) HPO42- d) H+ e) OH- f) K+
March 25, 2015 by James Alonso
A buffer is made up of .300 L each of .500 M KH2PO4 and .317 M K2HPO4. Assuming tha the volumes are additive, calculate a) the pH of the buffer b) the pH of the bugger after the addition of .0500 mol of HCl to .600 L of the buffer. c) the pH of the buffer after the addition of...
May 1, 2007 by James
Problem: Need to prepare a 250 mL buffer of pH 7.00 using equimolar K2HPO4 and KH2PO4 solutions. Ka for phosphoric acid: Ka1=7.2 x 10^-3 Ka2=6.3 x 10^-8 Ka3=4.2 x 10^-13 I though the hard part of this was picking the right equation/Ka value, but I am not getting the right ...
February 22, 2015 by lauraK
A buffer solution of volume 100.0 mL is 0.140 M Na2HPO4(aq) and 0.120 M KH2PO4(aq). What are the pH and the pH change resulting from the addition of 55.7 mL of 0.0100 M NaOH(aq) to the buffer solution?
October 21, 2014 by Jessica
What is pH of the buffer 0.1 mol L-1 Na2HPO4/0.15 mol L-1 KH2PO4? (Given Ka(H2PO4-)=6.2x10 power-8). Sorry if the power is confusing. My computer does not have the symbol. Thanks
October 22, 2010 by Elleni
A 1L of buffer was prepared from 0.15 mole of Na2HPO4 and 0.10 moles KH2PO4. a) What is your pH and what is the pH change that adding of 80.0 mL of 0.100 mol L-1 NaOH cause? b) What happen to the pH after adding 10.0 mL of 1.0 mol L HNO3-1.
April 28, 2011 by Margo
You need to use KH2PO4 and K2HPO4 to prepare a buffer with a pH of 7.45. Which of the following ratios of [base]/[acid] is required? For phosphoric acid, (H3PO4), Ka2 = 6.2 × 10–8. Do I use the Hasselbach equation?
March 23, 2016 by Jenny
Pharmaceutical Dosage Forms
If there is 1 g KH2PO4 and 1 g K2HPO4 in 100mL of solution, what is the mEq/mL of potassium? The Answer is 0.19mEq/mL. But I need to show work on how to get the answer. Textbook Applied physical pharmacy By Mansoor M. Amiji, Beverly J. Sandmann Chapter 3
November 30, 2010 by Jay
Calculate the pH of a potassium phosphate buffer if the pKa of KH2PO4 is 7.2 and the acid-base ratio is 2:1 I took Chemistry 7 years ago and am in a review for a Biochem course I am takin. I do not remember the basics so any help with how to get started or what equations to ...
August 18, 2015 by Liz
using the following salts listed below, calculate the moles of acid and conjugate base needed to make 100 ml of 0.50 M, ph 6.5,6.7, and 6.8 phosphate buffer solution. (For H2PO4-, pka=6.64) Salt Molar mass, g/mol KH2PO4 136.09 NaH2PO4*H2O 137.99 Na2HPO4*7H2O 268.09 K2HPO4 174.2
October 28, 2012 by alleyx3
1. A buffer was prepared by dissolving 11.7 g of KH2PO4 in 400 mL of water, and with the addition of concentrated solution of KOH the pH was adjusted to 7.10. The volume was then adjusted to 500 mL. What are the [PO43-], [HPO42-], [H2PO41-], and [H3PO4]? Use pKa values of 2.12...
February 24, 2014 by James
As a technician in a large pharmaceutical research firm, you need to produce 400. mL of 1.00 M potassium phosphate solution of pH = 7.18. The pKa of H2PO4- is 7.21. You have 2.00 L of 1.00 M KH2PO4 solution and 1.50 L of 1.00 M K2HPO4 solution, as well as a carboy of pure ...
February 28, 2011 by Anonymous
Calculate the pH of the following buffer solutions: a) a solution made by dissolving 2.733g KH2PO4 and 4.508g K2HPO4 in water to give 250 ml of solution. b)a solution made by mixing 35.00 ml 0.24 M C6H5NH2 with 15.00 ml 0.19 M C6H5NH3CL. The base dissociation constant Kb is 4....
February 8, 2012 by Karie
Hi I tried to understand this but I don't know why the answer is B: Which one of the following pairs cannot be mixed together to form a buffer solution: A) NaC2H3O2, HCl B)RbOH, HBr C) NH3, NH4Cl D) H3PO4, KH2PO4 E) KOH, HF The answer is B but could you explain why? I know its...
March 21, 2010 by Kiki
Molecular cell Biology
The following chemicals have the indicated formula weights:Sucrose-342.3,Potassium dihydrogen phosphate(KH2PO40-136.09,Tris -121.14.You also have the following solutions made:20%SDS,5M NaCl,500mM EDTA.You have a 40%glycerol solution and 10X TBE.List the steps to make the ...
January 18, 2014 by Caroline
A 1X Phosphate Buffered Saline solution was prepared by adding 1.44g of Na2HPO4 and 1.44g of H2PO4- to 800mL of water. Additional components were dissolved in the solution: 8g of NaCl, 0.2g of KCl and 0.24g KH2PO4. The resulting buffer solution had a pH of 7.2. a. Calculate ...
April 28, 2015 by Nicole
A buffer solution of volume 100.0 mL is 0.150 M Na2HPO4(aq) and 0.100 M KH2PO4(aq). Refer to table 1. (a) What are the pH and the pH change resulting from the addition of 80.0 mL of 0.0500 M NaOH(aq) to the buffer solution? pH pH change (include negative sign if appropriate) (...
March 16, 2010 by Trixie
Online chemistry lab preparing standards help? I was told to prepare some standard for a chemistry lab and here where the instructions: Obtain a solution of known phosphate concentration. In this lab we will use (1.e-002M) potassium dihydrogen phosphate, KH2PO4. Note the ...
July 1, 2009 by Gweedo8