Hi Xavik, I think that many people transfer the solid directly to the flask. That is not wrong. I have found that it is easier to get every bit transferred by dissolving a little bit at a time. It often helps speed up the process of dissolving. (Actually, I learned this from my mentor who was especially good at this sort of technique.)
Greetings Mr. Gary, I am current student of Higher School of Chemistry (associate degree student) and in lab of Analytical chemistry, I am using very similar method of filling volumetric flasks, but our teacher told me that this method is totally wrong (she got Engineer degree from University of Chemistry and Technology in Prague). She is always saying that we need to use a funnel and fill flask near to mark spot, and then use pipette to fill it directly to the mark (that means liquid cannot touch the walls of flask). Can you help me in some way ? I would like to know real and correct answer for this problem because it seems every person is this doing their way but I am taught to do it my way from chemistry labs where I did my practice work, but our teacher hates it. Thank you for the answer
Hi Serq, using a funnel to transfer the solution to the flask is a good method. If you use a funnel, be sure to rinse it well and remove it before bringing the water to the mark with a disposable pipet. Many people feel more confident pouring the bulk of the liquid with the help of a funnel and that is fine. If the water does touch the inside wall of the flask, it is not a problem if you give it time to drain down to the meniscus and gradually bring it to the mark. The main objective is to transfer every trace of the weighed material into the flask before filling to the mark (and mix well).
Thanks for the video. I was taught to always add the solid to the volumetric flask and not to a previous flask. At first I did like in the video, dissolving the solute in a small quantity of solvent and adding slowly, but I was told it was wrong. Were they right? Maybe it only matters for very precise measures?
Hi Xavik, I think that many people transfer the solid directly to the flask. That is not wrong. I have found that it is easier to get every bit transferred by dissolving a little bit at a time. It often helps speed up the process of dissolving. (Actually, I learned this from my mentor who was especially good at this sort of technique.)
Greetings Mr. Gary,
I am current student of Higher School of Chemistry (associate degree student) and in lab of Analytical chemistry, I am using very similar method of filling volumetric flasks, but our teacher told me that this method is totally wrong (she got Engineer degree from University of Chemistry and Technology in Prague).
She is always saying that we need to use a funnel and fill flask near to mark spot, and then use pipette to fill it directly to the mark (that means liquid cannot touch the walls of flask). Can you help me in some way ? I would like to know real and correct answer for this problem because it seems every person is this doing their way but I am taught to do it my way from chemistry labs where I did my practice work, but our teacher hates it.
Thank you for the answer
Hi Serq, using a funnel to transfer the solution to the flask is a good method. If you use a funnel, be sure to rinse it well and remove it before bringing the water to the mark with a disposable pipet. Many people feel more confident pouring the bulk of the liquid with the help of a funnel and that is fine. If the water does touch the inside wall of the flask, it is not a problem if you give it time to drain down to the meniscus and gradually bring it to the mark. The main objective is to transfer every trace of the weighed material into the flask before filling to the mark (and mix well).
Thanks for the video. I was taught to always add the solid to the volumetric flask and not to a previous flask. At first I did like in the video, dissolving the solute in a small quantity of solvent and adding slowly, but I was told it was wrong.
Were they right? Maybe it only matters for very precise measures?