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I have a question that asks if the buret tip is not filled before the experiment what would happen (effect on molarity for acid/base titration). The way I'm thinking about it, it's not like you're putting a pre measured solution into it. You fill it as high as you fill it and you can't put anything in without getting the tip filled up too, so I don't see where that will change anything. Am I thinking about that right?

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You fill it as high as you fill it and you can't put anything in without getting the tip filled up too,

No I don't think it will work like that. Usually you have the stock or valve closed at the bottom. Consequently, the tip will be empty until you bleed the buret. Further, you will often bleed (allow the titrant to flow) a buret while thumping the tip to remove any air bubbles that may form directly under the stop-cock when your titrant flows initially through the tip. Once you have titrant in the tip and the tip is devoid of air bubbles you will then close the valve and fill the buret to the desired level.

At this point you can better determine just how much you have used.

The measure marks on the buret itself take into account what is in the tip below the stop cock. But if you do not bleed the tip initially, filling it with your titrant then your first addition will be a bit off because the tip does not fill entirely with liquid before you allow some to drip through.

Here is a good write-up on titrations with burets.

A bubble in the nozzle of a buret will produce an inaccurate volume reading if the bubble escapes during a titration. Bubbles may be large and visible as shown above left or so small as not to be seen, above center. During a titration such small bubbles begin to move in the direction of the nozzle but may remain in place even though there is a moderate flow of titrant (above right). Even when the buret valve is wide open some bubbles remain in place until you take your eyes off them. Then they sneak through the nozzle and ruin your titration. Also if you let a an air bubble stay because you think it will remain and then later it leave to the tip you will have to start over because you have no idea what

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I'm assuming that the question is talking about leaving air in the tip of the buret once you've filled it. In that case you would actually be adding less solution than you would have measured because the first half mL or so would go into filling the tip.

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Yea, but in the lab we didn't measure any amount ahead of time, just filled it to the markings on the buret that we wanted.

(sory for the annonymous post as an answer, away from my comp and coudn't remember my password to log in on this one.)

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