April 16, 2014

Homework Help: chemistry lab

Posted by amanda on Friday, February 1, 2008 at 10:54pm.

Could someone help me with this? i am tired of it.

here is my data from lab:
Buffer1: HPO4- weight 3.412g; original pH
Buffer 2: HEPES wt: 1.090g original pH 10.08

pH of 0.1M: 7.5;
pH of 0.01: 7.72;
pH of 0.001M: 7.87

PH of 0.1M: 7.5
ph of 0.01 M: 7.42
pH of 0.001M: 7.42

The problem will be made for one of the buffers made.

A) What is the ratio of A-/HA in your buffer after you adjusted its pH to the required value? (pH goal: 7.5)

B) How many micromoles of A- and HA are present in the solution?

C) If you now add 3 mL of 1 M NaOH, will you still have a valid buffer?

Thanks, i have been trying to wok this for hours.

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