# Amount of starting material needed for Buffer

1. Sep 11, 2008

### thephoenician

given .1M of formic and .1M formate, how do you make 40 ml of .1M Buffer ph=2.9

basically it's going to equal .141=$$\frac{base}{acid}$$ after going through henderson hasselbach

Does anyone know how to do this using an ICE table?

2. Sep 11, 2008

### Staff: Mentor

ICE table is of no use here.

You have two equations. Total volume:

$$V_{base} + V_{acid} = 40$$

and ratio of concentrations (as given by Henderson-Hasselbalch equation):

$$\frac {0.1*V_{base}} {V_{base} + V_{acid}} = 0.141 * \frac {0.1*V_{acid}} {V_{base} + V_{acid}}$$

Note that what I have put on both sides is just amount of substance divided by total volume, nothing fancy. Just solve.

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