At the beginning of a titration to standardize the NaOH solution, Student A adjusted very carefully the initial burette volume to 0.00 mL, but he did not notice an important air bubble in the tip of the burette. At the end of the titration, the air bubble is gone. Explain the effect of that mistake on the calculated molarity MB. (Will the experimental MB calculated by Student A be higher or lower than the true MB value?)
McGill chem lab report?
The bubble is gone which means the volume measured is the volume of the titration + the volume of bubble; i.e., it is too large.
If you are doing a titration with acid so that mL acid x M acid = ml base x M base, then
Mbase = mLacid x Macid/mL base
So mL base is too large how will that affect the answer?
Well, isn't that a bubbly situation! When Student A failed to notice the air bubble in the tip of the burette, it actually affected the calculated molarity of NaOH. You see, during the titration, the air bubble could have caused an underestimation of the volume of NaOH solution delivered. This means that the experimental molarity calculated by Student A will be higher than the true molarity.
It's like thinking you're drowning in soda, only to realize you're just swimming in it. The presence of the air bubble made it seem like more NaOH solution was used than actually was. So, Student A should be prepared to lower their expectations a bit when it comes to the calculated molarity. Sometimes, it's better to give the bubbles a break!
The effect of the air bubble in the burette tip on the calculated molarity (MB) of the NaOH solution is that it will be lower than the true MB value.
When Student A adjusted the initial burette volume to 0.00 mL, the presence of the air bubble in the burette tip meant that the actual volume of NaOH solution delivered was less than what was recorded. This is because the air bubble took up some space in the tip, displacing some of the NaOH solution.
During the titration process, the NaOH solution was slowly added to the analyte solution. The air bubble would have gradually moved up the burette as the solution flowed, eventually disappearing at the end of the titration. This means that the recorded volume on the burette at the end of the titration includes the volume of the air bubble that was initially present.
Since the recorded volume includes the volume of the air bubble, the calculated molarity (MB) will be lower than the true MB value. This is because the recorded volume is higher than the actual volume of NaOH solution delivered, resulting in a calculated molarity that is lower than the true molarity of the NaOH solution.
The effect of having an air bubble in the tip of the burette during a titration can potentially lead to the calculated molarity (MB) being higher than the true value.
During titration, a solution of known concentration (in this case, NaOH) is added to another solution of unknown concentration until a reaction between the two is complete. The point at which this reaction is complete is called the endpoint and is typically determined by the appearance of a color change or the completion of a chemical reaction.
The burette is used to accurately measure the volume of the NaOH solution being added to the other solution. However, if there is an air bubble in the tip of the burette, it can prevent the NaOH solution from flowing properly and may result in incorrect volume measurements.
In this scenario, Student A adjusted the initial burette volume to 0.00 mL, but due to the hidden air bubble, their initial volume measurement is inaccurate. As the titration progresses, the air bubble may move up the burette and eventually disappear. This means that the NaOH solution was dispensed starting from a volume greater than 0.00 mL, leading to an overall higher volume of NaOH solution being used in the titration.
Since molarity (MB) is calculated by dividing the moles of solute by the volume of solution, a larger volume measurement would result in a smaller calculated concentration or molarity value. However, in this case, due to the initial incorrect volume measurement caused by the air bubble, the calculated MB will be higher than the true MB value.
Therefore, the mistake made by Student A will likely result in an experimental MB that is higher than the true MB value.