[washey]

Would you expect a Solution of .00015M I2 to increase to a .000172M I2 solution over a 5 week period?

This is a question of my own, that I encountered in my lab. The .00015M is the caluculated, and the .00172M is my number from titration. It would make sense to me that the molarity would increase over time, but not everything that makes sense is the correct answer. Just looking for someone to back me up on this.

[macman104]

Would you expect a Solution of .00015M I2 to increase to a .000172M I2 solution over a 5 week period?

This is a question of my own, that I encountered in my lab. The .00015M is the caluculated, and the .00172M is my number from titration. It would make sense to me that the molarity would increase over time, but not everything that makes sense is the correct answer. Just looking for someone to back me up on this.

Maybe? I mean, could some of your solution evaporated, thus increasing the molarity?

[washey]

That's exactly what my theory is based from. I believe that if some of the water had evaporated out of the solution, the increased molarity would be explained.

I got the same results from Fresh orange juice versus week old orange juice.

[Borek]

The .00015M is the caluculated

How? And what kind of solution? I₂ in KI? Have you checked if it was 0.00015 after preparing the solution?

[washey]

The solution was taken off of the shelf with an indicated .0015M. We used titration to determine that the actual was.00172, using a solution of Ascorbic acid and H2O. (.05g C6H8O6 in 100ml of H20)
After four fine tirations with the same value of 16.05mL of I2 needed for titration, we used the formula M1 x V1 = M2 x V2, and came up with .00172M I2.

[Borek]

Who, how and when prepared the solution? I mean - could be it dried out changing the concentration, but could be it was not 0.0015 from the very beginning. From what you wrote it could well be the case.

[washey]

Try not to get too carried away with this. This is just a wonder, of what causes it. This was from am online lab, for my Chemistry class.
The original solution was provided with an indicated .0015M. They asked us to Titrate the solution to find its true value, to be used later in an attempt to find the concentration of ascorbic acid in fresh orange juice and week old orange juice.

[Borek]

Could be 0.0015M was only an approximated value, especially if you were asked to determine iodine concentration first.