# Chemistry

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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 4.00 X 10^-10 for C6H5NH2. Assume that the final volume is the sume of the volumes of the two solutions that are mixed.

• Chemistry - ,

Use the Henderson-Hasselbalch equation. If you get stuck explain what it is you don't understand.

• Chemistry - ,

I don't understand where to start. Do i turn the grams given in part a) to moles first? then i am not sure what to do

• Chemistry - ,

Yes, convert g to moles. Look up the Ka value for the acid and convert that to pKa, then plug into the HH and calculate pH.

• Chemistry - ,

how would you do part b?

• Chemistry - ,

you have 20 ml of 0.1 M aqueous solution of the weak base (CH3)N (Kb = 7.4 x 10^-5). This solution will be titrated with 0.1 M HCl.

how many ml of acid must be added to reach the equivalence point?

• Chemistry - ,

a) 7.432