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Justin Mueller
Приєднався 13 лют 2016
Acid-Base Chemistry II Difficult Exam Review Question
The question:
A buffer is prepared by adding 150 mL of 1.0 M NaOH to 250 mL of 1.0 M NaH2PO4. How many moles of HCL must be added to this buffer solution to change the pH by 0.18 units? If necessary, assume the total volume remains unchanged at 400 mL.?$&&
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A buffer is prepared by adding 150 mL of 1.0 M NaOH to 250 mL of 1.0 M NaH2PO4. How many moles of HCL must be added to this buffer solution to change the pH by 0.18 units? If necessary, assume the total volume remains unchanged at 400 mL.?$&&
Zb
Переглядів: 5 018
Відео
ICE Tables made EASY!
Переглядів 298 тис.8 років тому
The problem: The following reaction has been studied at 25C: 2BrCl [equilibrium symbol here] Br2 Cl2 The Equilibrium constant Kc is known to be 0.141. If the initial concentration of chlorine is 0.0300 M and of bromine monochloride is 0.0200 M, what is the equilibrium concentration of bromine? General Chemistry II ICE Table Initial, Change, Equilibrium Chemical Equilibria
muito obrigado
Wish I found this in first year lol.
Explaining where the positive X goes and the negative X depends entirely what you start with. A lot of Equilibrium questions start with ONLY reactants and NO products, which means the concentrations of the REACTANTS can ONLY go down (thus -x), and the products can ONLY go up. KEEP IN MIND THO that the x values might be multiplied by the coefficients. So 2 moles of reactant mean you have to subtract (-2x) in the CHANGE portion of the RICE table. OTHER equilibrium questions have partial quantities of Reactants and products IN THIS CASE because one product is at ZERO, the products MUST GO UP (thus +x or +2x or +3x). HOWEVER in other questions equilibrium is established, and you must figure out what happens to the equilibrium happens when either more product or reactant is added. This might require calculating a TRIAL K value. Trial K values that are SMALLER than the actual Keq value provided MUST shift towards the products(thus +x goes on the product side of the CHANGE line and -x goes on the reactant side. Trial K values that are BIGGER than Keq means the shift goes towards the REACTANT SIDE (which would use +x in the CHANGE LINE and -x for the products on the CHANGE LINE). Understanding this is important.
The ONLY thing I wished you showed, was step by step the quadratic formula part, but oh well. I get the gist. Thank you!
It was so great UNTIL YOU COMPLETELY LOST US IN THE MATH.
can you not show how to solve the quadratic too???
i missed a week of school and this video caught me up to speed you are a godsend
dude, this video helped so much..thanks
why didnt you show us how you put into quad. equation?????
Bro cooked 2 vids and dipped we need you come back. It takes so long to find someone who explains in full detail in a short amount of time.
Thank you this video was really helpful.
w
Finally thanks to this gentleman I understand ICE Method 😊
he was explaining everything so well until the .08x he just skipped over without explaining what's happening or how he got the answers :((
He derived it when squaring the (0.02 - 2x). If you use the foil method and multiply (0.02 - 2x) and (0.02 - 2x) -2x * -2x = 4x^2 -2x * 0.02 = -0.04x 0.02 * -2x = -0.04x 0.02 * 0.02 = 0.0004 If you add the -0.04x + -0.04x = -0.08x If you still don't understand, you should watch a video on squaring using the FOIL method :)
what if Kc wasn't given?
my goat thank you!
THANK YOUU!!!
Not to be weird-but you sound like you’re handsome. Thanks for the help!
How did u get .0004??
its from the squared value of (0.02 - 2x), its was squared because there were 2 mols of BrCl in the given chemical equation
I love you wallahi
this was amazing I've been so confused on the signs for x, thank you so much!!!!!!!!
I love you you showed me in 6 minutes what a website wasn't able to show me in 6 hours
thanks...
great video
make more videos!!
thanks
Everyone is saying this is perfectly explained but he did not explain how he got the -.08 for 4x2-.08=.0004....I see how we got 4x and the .0004 but not the middle number.
foil
It's an identity to expand squares of variable numbers. In this question he used a²-2ab+b²
Quick question during the last part the quadratic, you get 2 answers why did you pick that answer and not the other?? 😁
Thank you Justin
bro i swear this helped so much I WAS STUCK ON A WUSSTION LIKE GHIS FOR A WHILE
thank you!
thank you so much who was know that you will help me after7 years
wh if i dont know math, i litreally didnt get it cuz its not explained from where u got the numbers at the end
He said he got it by the calculator bruv
Thank you for this video! You made my life a lot easier XD. For your first video this was really intuitive.
mwuah 😙
this was off
How did you get .08x for the denominator ? im so confused on how to do these types of problems & you didn’t go into enough detail on how to actually solve the problem you rather implemented the answers you got onto this paper without fully explaining how to get the values being written down
i think i love you
You're literally the best human in existence
Thanks u😢😢😢😢
How math? Idk how factor? How you factor? Why you factor that way? Why?
The forbidden knowledge!
holy crap this is finally answered my burning question of "why tf is it the change negative?!?!?!?!"
hey man thank you so much for this video im like 6 years late but for years i havent been able to understand ice tables. You are the best I am saved 💜
Thank you! I got it :)
THANK YOU SO MUCH! the best video I've seen
U EXPLAIN BETTER THAN MY CHEMISTRY TEACHER!
thank u
wow, this is not complicated atall... thanks (From the future)
This was so confusing. Would of been best if he showed all the steps