Hi thank you so much for the videos, I just have one question. When calculating the Rf value and you measure the distance travelled by the component , do you measure up to where the spot starts or when the spot ends (the bottom the the spot or the top)? I don't know if it makes sense...😩
Thank you very much for the videos !!! I just had one question, are these videos for OCR A as well as I didn't know about the % of component or the calibration curve.
1:56 (TLC): I have never understood why the compound that has the weakest adsorption is the one at the top and why the best adsorbent is at the bottom. And what does it imply about the polarity of the compound? Could you help me please? Thanks!
Inigo Bergua The stronger the level of adsorption the more the component ‘grips’ to the stationary phase and hence is moved less by the mobile phase. The polarity question is more relevant to a liquid stationary phase (at A level anyway) and that’s found in gas chromatography. So if you have a polar substance being used for a liquid stationary phase then a polar component will interact more and spend more time in the stat phase and less in the carrier gas so retention time will be longer. If component is non-polar the opposite it the case and a shorter retention time. Situation reversed if a non-polar liquid stationary phase is used. Hope that makes sense. I do that other videos on chromatography btw. 😊
Thank you so much! I had been checking youtube again and again just to see you upload this for this was exactly what I needed.
hi sir at 7:35 for the % component of a mixture do we need to x100 to make it a percentage? thanks for the great video btw!
Hi thank you so much for the videos, I just have one question. When calculating the Rf value and you measure the distance travelled by the component , do you measure up to where the spot starts or when the spot ends (the bottom the the spot or the top)? I don't know if it makes sense...😩
I tried an exam question and got the correct answer by measuring the distance of the 'centre' of each spot from the pencil line
Thank you ☺️
Thank you very much for the videos !!! I just had one question, are these videos for OCR A as well as I didn't know about the % of component or the calibration curve.
Yes they are - have you seen this? ruclips.net/video/4UqzSZqzXtU/видео.html
@@MaChemGuy Thank you very much for the very quick response !!!! I am ever so grateful for all these videos :):)
1:56 (TLC): I have never understood why the compound that has the weakest adsorption is the one at the top and why the best adsorbent is at the bottom. And what does it imply about the polarity of the compound? Could you help me please? Thanks!
Inigo Bergua The stronger the level of adsorption the more the component ‘grips’ to the stationary phase and hence is moved less by the mobile phase. The polarity question is more relevant to a liquid stationary phase (at A level anyway) and that’s found in gas chromatography. So if you have a polar substance being used for a liquid stationary phase then a polar component will interact more and spend more time in the stat phase and less in the carrier gas so retention time will be longer. If component is non-polar the opposite it the case and a shorter retention time. Situation reversed if a non-polar liquid stationary phase is used. Hope that makes sense. I do that other videos on chromatography btw. 😊
I understood both answers. Thanks from Spain, I really appreciate the effort you put in your YT channel!
Inigo Bergua Thanks for that. You are very welcome. Sending my best wishes to you
@ 4.26 Isn't the liquid 'absorbed' instead of 'adsorbed' onto solid support??
Great vid btw!!
No solids dont absorb stuff
Will we have to plot a calibration curve in the exam? if so please can you do a video explaining how to
Annabel B I already have
Do we still need gas chromatography?
For OCR A
@UCRihz3llLpHJh88cwiyN6tQ yup