Calculating Equilibrium Constant and Making a Buffer with NH4Cl and NH3

[BThomas1219]

Homework Statement

Calculate the equilibrium constant if you are given gibbs energy for the following molecules
NH3=-26kJ/mol
H2O-237.13kJ/mol
NH4+=-79.31kJ/mol
OH-=157.3kJ/mol

How many moles of NH4Cl must be added to 1.0L of 0.10M NH3 to make a buffer whose pH is 9.0?

Homework Equations

Henderson hasselbach equation,
delta G=RTlnK

The Attempt at a Solution

1) How do you calculate equilibrium constant if you don’t have the temperature to use G=RTlnK
2) For the second half the question, I am thinking of using Henderson hasselbach equation to determine the concentration of NH4Cl. If not, how should I go about solving this question.

 

[BThomas1219]

Just need some help starting out with the problem

 

[Doobwa]

I believe unless otherwise stated, you assume T=298.15K (standard conditions).

I'm not familiar enough with buffer solutions to help with the rest, sorry!

 

[Borek]

Once you have K, Henderson-Hasselbalch is the way to go.