[m2009]

I have this question:

What is the pH of a solution made by dissolving 6.75 g of NH4Cl and 2.80 g of NH3 in 200ml of water the Ka for ammonium is 5.6 x 10^-10.

The answer i came up with is 3.20. Did I get the right answer or did i do something wrong


I also have another problem:

The following reaction occurs at 1000 degree celcius with a Kc of 255. What are the equilibrium concentrations of all reactants and products if originally you have 0.250M [CO] and 0.175M [Cl2]?


when i try to solve the quadratic for this problem i keep getting two positive numbers. am i doing something wrong here or am i suppose to use one of those numbers? ( i get 0.26 and 0.17 )

[Borek]

The answer i came up with is 3.20. Did I get the right answer or did i do something wrong

No, that's wrong. This solution should be alcalic, something like 10 or around.

This is a buffer question, you should use Henderson-Hasselbalch equation.

when i try to solve the quadratic for this problem i keep getting two positive numbers. am i doing something wrong here or am i suppose to use one of those numbers? ( i get 0.26 and 0.17 )

Not checking these numbers validity: getting two different answers is nothing unusual in such situation. Usually one has no physical sense (like for example negative concentrations or mass is not conserved).

[m2009]

Thanks so much. I worked it out again using that equation and I got an answer close to what you said I would. I also think I figured out my problem with the quadratic.