Final answer:
The presence of an air bubble in the buret during Shane's rough titration affects the measured volume of EDTA, leading to a false calculation of its concentration.
Step-by-step explanation:
Yes, the presence of an air bubble in the buret tip during Shane's rough titration of EDTA would affect the calculated concentration of EDTA. When an air bubble is present, it takes up space that would otherwise be filled by the titrant solution. This means that the actual volume of EDTA delivered to the solution is less than what the burette readings suggest. If not corrected, this would lead to a calculation of a falsely high concentration of EDTA since the volume delivered appeared greater than it actually was. However, since Shane continued with two fine titrations after the bubble was removed, only the rough titration would be affected. In practice, rough titrations are often disregarded in favor of the more accurate fine titrations when calculating the final concentration.
Since the rough titration is typically used to approximate the endpoint and not for precise measurements, the impact on the final calculated concentration should be minimal, assuming the fine titrations were accurate. A good analytical practice would involve repeating the rough titration if such an issue were noticed, to ensure all titrations are consistent and reliable for the calculation of EDTA concentration.