You sir saved my chemistry grade. I got a D in my internal exam in the spring, but after watching all of your playlists for each paper and studying I think I’m due an A in this exam. Really, thank you.
if given this information: 2.5g of I2 and 1.67 g of KI per dm3 of solution. How do you calculate the concentration of iodine in I2 + 2S2O3 2- → 2I- + S4O6 2-
if given this information: 2.5g of I2 and 1.67 g of KI per dm3 of solution. How do you calculate the concentration of iodine in I2 + 2S2O3 2- → 2I- + S4O62-. Please I need this for an exam
It means dissolve 2.5 g of I2 in 1.67g of KI solution and make it up to 1dm3. Iodine is a solid that can be dissolved using KI solution and not water. I hope this helps.
Thanks, I think I came across a question where they asked us this. This is what I found on the internet. "As to why it is added near the end of the titration rather than at the beginning is because the starch-iodine complex at high I2 concentrations is relatively stable. The release of I2 from the starch-iodine complex is slow at high I2 concentrations. As we are looking for the discharge of the blue black colour, we will end up adding more titrant thinking that the end point has not been reached when in fact, the decolourisation would take place if the iodine was given time to dissociate."
![[UNCUT] “อภิสิทธิ์” ครม.อุ๊งอิ๊ง แย่งเก้าอี้กันฝุ่นตลบ “ทักษิณ” บงการเอง Iคนดังนั่งเคลียร์I 21ส.ค.67](http://i.ytimg.com/vi/a_b-kItw2jY/mqdefault.jpg)
You sir saved my chemistry grade. I got a D in my internal exam in the spring, but after watching all of your playlists for each paper and studying I think I’m due an A in this exam. Really, thank you.
Best of luck!!
@@MaChemGuy had a great paper 3! And the colour change equilibrium prediction was spot on… awesome.
this is amazing thank you for carrying my chemistry
good luck tomorrow
@@hamz_012 thanks brother you too if you've got an exam
What would the oxidising agent be? Thanks so much for this video!
the one most likely to be reduced ie gain electrons so if you think electro negativity the closer to fluorine metaphorically
Hi, I did the Jan 11 F325 paper where mole ratio did exist in the last question.
if given this information: 2.5g of I2 and 1.67 g of KI per dm3 of solution. How do you calculate the concentration of iodine in I2 + 2S2O3
2- → 2I- + S4O6
2-
can someone provide me a link where this titration procedure is clearly described from the beginning.Thanks in advance!
This is for the exam tomorrow !! Do we need to learn the titration equations? How much detail do we need to memorise please?
Thank you so much
X C Hbbb Says in specification that equations will be given
Do we need to know the method ?
Please give the this video with all reaction nd process for iodine valua acc to Wijs Solution ...
if given this information: 2.5g of I2 and 1.67 g of KI per dm3 of solution. How do you calculate the concentration of iodine in I2 + 2S2O3
2- → 2I- + S4O62-. Please I need this for an exam
It means dissolve 2.5 g of I2 in 1.67g of KI solution and make it up to 1dm3. Iodine is a solid that can be dissolved using KI solution and not water. I hope this helps.
Thanks
Why do we add starch towards the end of the experiment and not the start?
Rukayya Saifuddin I guess it would work either way. That’s the official method
Thanks, I think I came across a question where they asked us this. This is what I found on the internet.
"As to why it is added near the end of the titration rather than at the beginning is because the starch-iodine complex at high I2 concentrations is relatively stable. The release of I2 from the starch-iodine complex is slow at high I2 concentrations. As we are looking for the discharge of the blue black colour, we will end up adding more titrant thinking that the end point has not been reached when in fact, the decolourisation would take place if the iodine was given time to dissociate."
Rukayya Saifuddin Thanks for that!! I think you’d be very unlucky to be asked that in an exam though.
What is the effect if the starch is added too early. Or does it not make a difference
The BioChem Guy I think it’s unstable at high concentrations of I2 so must add near the end
Starch solution forms an insoluble complex with higher concentration iodine solution