# CHEMISTRY

Using a 0.20 M phosphate buffer with a pH of 6.5, you add 0.72 mL of 0.46 M NaOH to 58 mL of the buffer. What is the new pH of the solution? (Enter your answer to three significant figures.)

I don't even know where to begin!! I just need a set up of the problem - without answers

1. 👍 0
2. 👎 0
3. 👁 560
1. You have two/three problems in one here. First I would determine the base and acid concentrations in the initial buffer. To do that use
pH = pKa + log (base)/(acid)
and solve for base/acid ratio.
Then you know acid + base = 0.2

Solve those two equation simultaneously to determine (H2PO4^-), the acid, and (HPO4^=), the base. I would then convert that to mols (or millimols) for the 58 mL sample. Let a = millimoles acid and b millimols base

............H2PO4^- + OH^- ==> HPO4^=
I.............a........0........b
C............ a-c.....-c........+c
E.............a-c......0........b+c

Then plug the E line back into a new HH equation and solve for the new pH.

1. 👍 1
2. 👎 1

## Similar Questions

1. ### Chemistry

Using a 0.25 M phosphate buffer with a pH of 6.6, you add 0.71 mL of 0.51 M HCl to 49 mL of the buffer. What is the new pH of the solution? (Enter your answer to three significant figures.) Using a 0.25 M phosphate buffer with a

asked by Sarah on March 6, 2019
2. ### chemistry

I have already posted this and never got a response, please help. here is my data from lab: Buffer1: HPO4- weight 3.412g; original pH Buffer 2: HEPES wt: 1.090g original pH 10.08 buffer1: pH of 0.1M: 7.5; pH of 0.01: 7.72; pH of

asked by student on February 3, 2008
3. ### chemistry

prepare a phosphate buffer with pH= 7 from solid NaH2PO4 (pKa =7.21) and Na2HPO4. 1) calculate the ratio of [CB]/[acid] I got the ratio as 0.62 2) calculate the mass of each component required to make 1L of a .1 M buffer solution

asked by prepare a phosphate buffer with pH= 7 on October 19, 2015
4. ### chemistry

an ezyme -catalysed reaction was carried out in a solution buffered with 0.05 M phosphate ph 7.2 . As a result of the reaction ,0.06M of acid was formed. (phosphoric acid has three pka values. The one required for this calculation

asked by josh on January 12, 2016
5. ### Chemistry

You are instructed to create 500. mL of a 0.25 M phosphate buffer with a pH of 7.7. You have phosphoric acid and the sodium salts NaH2PO4, Na2HPO4, and Na3PO4 available. (Enter all numerical answers to three significant figures.)

asked by Sarah on March 6, 2019
1. ### Chemistry

1.What is the pH of a solution containing 0.042 M NaH2PO4 and 0.058 M Na2HPO4 ? The pKa of sodium phosphate is 6.86. pH = 6.86 + log [0.058] / [0.042]; pH = 6.86 + 0.14; pH = 7.00 That is my answer to the above question. The

asked by Blake on January 27, 2013
2. ### science

How do i prepare 0.1 ml KH2PO4-KOH buffer, PH 7.4 (20mM)? Deoxyribose (2.8mM) - EDTA (0.1 mM) - H2O2 (1mM) - vaniline10 mM - phosphate buffer pH 6.9 - Phosphate buffer, 20mM - Phosphate buffer 0.1 M (pH 7.4) - Ascorbate (0.1mM). (

3. ### chemistry

Assignment 1 Question Consider a monohydrogen phosphate ( HPO42-) and dihydrogen phosphate (H2PO4-) buffer solution. [HPO42-] = 0.063M [H2PO4-] = 0.10M What happens when you add 1.0 ml of 0.10 M HCl to the a 99ml solution? What

asked by anonymous on January 26, 2013
4. ### Biochemistry

you have a 0.200L of solution containing 250mM phosphate buffer, pH 6.8. An equivalent amount of HCl/NaOH with respect to the total amount of phosphate in the buffer --> mmol of NaH2PO3 + mmol of NaH2PO4 = 50 mmoles. What would

asked by Abba on May 18, 2015
5. ### Chemistry

Using a 0.20 M phosphate buffer with a pH of 6.7, you add 0.71 mL of 0.55 M HCl to 52 mL of the buffer. What is the new pH of the solution?

asked by Ashlee on February 27, 2015
6. ### Biochemistry

you have a 0.200L of solution containing 250mM phosphate buffer, pH 6.8. An equivalent amount of HCl/NaOH with respect to the total amount of phosphate in the buffer --> mmol of NaH2PO3 + mmol of NaH2PO4 = 50 mmoles. What would

asked by Abba on May 16, 2015