Am I doing this right?

Question

Ok so I'm a senior in college trying to remember chemistry from long long ago. Specifically weak base titration. We have a solution of ammonia in water and we titrate it with 1.04 M HCl and have to figure out the number of moles of ammonia. So I use the amount of HCl used to find the moles of H+ present. The moles of H+ is equal to the moles of OH-. Then I used
Kb = [NH4+][OH-]/[NH3] to find out how much NH3 was in the water. It makes sense to me and seems to be right bt I don't remember for sure.

Answer 1

Chem's been a long time ago for me... a really, really long time ago. But, I think you're right, nothing jumps out at me and screams you're wrong. To be honest, chemistry was never my strongest subject (not my worst either, but I never had a passion for it like I did physics or electronics).

There's a good Wiki article on this, though:
http://en.wikipedia.org/wiki/Titration
Hope that helps.

Answer 2

No, you are wrong.

NH3 is the formula in the gaseous state. In aqueous solution it is practically NH4OH and the reaction with HCl is
NH4OH + HCl -> NH4Cl + H2O

The endpoint of the titration is when the titrant HCl and the unknown (ammonia) have reacted completely (regardless if there is hydrolysis of the salt, like in this case; NH4+ hydrolyzes and the pH at the endpoint is <7).

Since the reaction is 1:1 you have
mole HCl =mole NH4OH =>
M1*V1=M2*V2
M1=1.04 M
V1= L HCl you added with the burette
V2= L of the ammonia solution

and you calculate M2.

If you want the mole and not the concentration, then those are equal to the mole of HCl (M1*V1)

Answer 3

Thats a hard question. I'm gonna have to go with
c-Dead baby jokes- final answer

Answer 4

i don't know,so try it and find out what happens

Answer 5

nope totally wrong

Answer 6

its Kb = [NH6+][OH-2]/[NH3]