determine the pH of a 0.116 M Ba(OH)2 solution at 25 degrees C.
i keep getting 13.06 for this answer, but the answer is 13.37 :S
what i do is i take the negative log of the concentration which is 0.9355 which is pOH.
i know that pH = 14 - pOH
so i get pH = 13.06
where am i going wrong ? :S
thanks for help in advance!
haha I'm guessing your studying off the old chemistry multiple choice exam for tommorow's chemistry exam at ryerson?
You assumed barium hydroxide is totally dissociated. The solubility product constant is 5E-3.
Anya, do you know how to do number 4 on the final chemistry exam. Please tell me.
i figured it out, i have to multiple the concentration by 2 because of the 2 hydroxides right?
and yes i do know # 4
you want to convert 0.0354 mg/mL at 1 atm to mol/L at 0.00036 atm.
so :
(0.0354 mg/mL) x ( 0.00036)
= 1.2744 x 10^-5 mg*CO / mL
then you just want to convert units)
1.27 *10^-5 mg*CO/mL is 1.27 * 10 ^-5 g/L
multiply that by 1 mole CO/ 28 g
yyou get 4.5 * 10 ^ -7
Yeah I see what you did. I did the same thing in a slightly different way and got 4.5X10^-5. I see my mistake now
you have:
P1/C1=P2/C2
-----------
P1=1 C1=0.0354
P2=0.00036 C2?
-----------
1/0.0354=0.00036/C2
then you cross multiplied and then converted the value 1.27X10^-5 from grams to mols.
================================
Do you know how to do 6 can you tell me?
Well, well, well, looks like we've got a pH mystery on our hands! Let's see if we can solve it together, shall we?
Now, the first thing to remember is that Ba(OH)2 is a strong base, which means it dissociates completely in water. Since it's a 0.116 M solution, we know that the concentration of hydroxide ions (OH-) is twice that of the barium hydroxide (Ba(OH)2).
So, let's start by finding the concentration of hydroxide ions:
OH- = 2 * 0.116 M
OH- = 0.232 M
Next, let's find the pOH:
pOH = -log(0.232)
pOH = 0.634
But hang on a second! The pOH you calculated is different from what you got. Are you sure you're not playing a prank on me? *wink*
Anyway, moving on, we can find the pH using the pH + pOH = 14 relationship:
pH + 0.634 = 14
pH = 13.366
And there you have it! The pH of the 0.116 M Ba(OH)2 solution is approximately 13.37, not 13.06.
So, my friend, it seems you made a whoopsie in your calculations. But fear not, the Clown Bot is here to provide some laughter along the way! Keep practicing and remember to double-check your work, because pH values can be quite the tricky little rascals.
To determine the pH of a solution, you need to consider the dissociation of the compound in question. In this case, Ba(OH)2 is a strong base that dissociates completely into Ba2+ and 2 OH- ions.
To find the concentration of hydroxide ions (OH-) in the solution, we need to consider the molar ratio between Ba(OH)2 and OH-. Since Ba(OH)2 dissociates into two OH- ions, we can multiply the molar concentration of Ba(OH)2 by 2 to find the concentration of OH- ions.
Concentration of OH- = 0.116 M Ba(OH)2 * 2 = 0.232 M OH-
Now, we can find the pOH by taking the negative logarithm of the hydroxide ion concentration:
pOH = -log(0.232) = 0.634
Finally, to find the pH of the solution, we subtract the pOH from 14:
pH = 14 - 0.634 = 13.366
The correct pH of the 0.116 M Ba(OH)2 solution at 25 degrees Celsius is approximately 13.37, not 13.06. So there was a slight calculation error in your working.