Chemical Forums
Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: dirknathan on September 20, 2012, 04:50:50 PM
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How many milliliters of 8.34×10−2 M Ba(OH)2 are required to titrate 54.40 mL of 5.24×10−2 M HNO3?
I can't figure out where the M of Ba(OH)3 comes into play?
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What reaction is occurring when you do the titration?
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I assume they are reacting with each other. This is the only information I've been given.
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To begin to figure this out properly, you will need to determine the balanced chemical reaction these reagents undergo. We'd like to see it from you, and then we'll try to give you more hints to relate the various molarities to each other.
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I assume they are reacting with each other. This is the only information I've been given.
I suppose you are expected to know what kind of reaction to expect when you mix strong acid and strong base.
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How many milliliters of 8.34×10−2 M Ba(OH)2 are required to titrate 54.40 mL of 5.24×10−2 M HNO3?
Ba(OH)2 + HNO3 :rarrow: BaNO3+ + H2O + OH-
Does that look correct?
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NO, that's not correct. An acid and base should neutralize each other completely. And no, we can't create negative ions singly. Why does barium no longer need its charge balanced in the product?
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Every strong acid,strong base reaction has the same net ionic equation correct?
Why won't M1V1=M2V2 work for this problem?
I assume the ratio of moles isn't one to one (or is it), but if the net ionic equation is the same...
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This (OH)2 is rocking my world.
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2HNO3 + Ba(OH)2 --> Ba(NO3)2 + 2 H2O
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Every strong acid,strong base reaction has the same net ionic equation correct?
I suppose, but that won't help you here, since you will have to use the molarity of the the actual reagents.
Why won't M1V1=M2V2 work for this problem?
No. I suppose you could test that by filling all the values in your formula, if you're missing too many, then you'll know it won't work.
I assume the ratio of moles isn't one to one (or is it), but if the net ionic equation is the same...
You'll know when you balance the equation
2HNO3 + Ba(OH)2 --> Ba(NO3)2 + 2 H2O
Good. Now, you have a balanced chemical equation. What are the units understood in a chemical equation? There are some units understood to be there, 'tho this is somtimes hard for a new student to see.
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I see coefficients and charges. Not sure what your are asking for?
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Yes, the coefficient '2' before the nitric acid, that means two ... what?
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atoms. I did notice that, I've been working with the titration on a piece of paper. Back to my orignal problem, how to use Ba(OH)2's molarity.
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I actually found a sample problem just like this, only problem, mole ratio is one to one. they used the formula I previously stated. This is a different story.
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No. Don't think of it as atoms. Chemistry has only barely reached the point when pick up one molecule, and react it with one other. Think of it as groups. What unit do we use to describe groups? You have a hint in that you have to use the molarity.
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A mole. sorry, I know it isn't an atom, but I find my self visualizing the number. which is still incorrect.
I've gotten the mole down, I know the basic of the titration problem. I've done plenty where it need the molarity and already offers the volume. But, this change has thrown me off. This is one of the problems that is assigned every week where our proffesor just happens to not cover. I want to learn! Don't confuse that idea. You are telling me things I have written down. It's tedious to type it out on here. Especially since it is my brain trying to unscramble this issue.
I have done several calculations, but I don't know how to involve the molarity of Ba(OH)2
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Great. You've figured out that the balanced chemical equation relates moles of the reactants and products. Now, you've been given molarity, do you know how to relate that with moles? Hint: You'll need another part, which fortunately, you've been given for both barium hydroxide solution and nitric acid.
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Got it. 16.8mL.
Thanks for the guidance.