Moles calculations examples - IGCSE Chemistry

[@Superninja-gc6yy]

this is the most straight forward and on to the point video I've ever seen for calculations. thank u

[@ChrisGozzardThatPhysicsGuy]

Thanks!!

[@baconlover1664]

This is the only resource that has helped me with moles calculations! I didn't understand moles calculations for two years so I am extremely happy to have found this!!! Thank you so much :-D

[@ChrisGozzardThatPhysicsGuy]

+Bacon Lover A pleasure.

[@NickMaini]

currently revising for chem igcse tomorrow, this was really useful, thank you Chris

[@ChrisGozzardThatPhysicsGuy]

Nick Maini Hope they go well Nick..

[@snowworm4601]

Same. 7 years later!

[@nethulbandara3445]

Deserves more loved it , got every bit of it ! Found it difficult but amazing how easy it it.

[@ChrisGozzardThatPhysicsGuy]

Great job!

[@abaislife]

Here 7 years after the video was uploaded. This was really helpful thanks

[@ChrisGozzardThatPhysicsGuy]

You're welcome!

[@Dark69bladeAE]

Sir at 1:45 you made a mistake you must multiply 32 by 2 and then add 64 and 2 .

[@ChrisGozzardThatPhysicsGuy]

Hi Dark69blade I don't see the mistake myself. Maybe someone else on here can check.

[@stephanjancso309]

chris, what about organic chemistry??

[@ishwarbhais]

Can somebody please explain me in the second some why do we divide the mole ratio by 2/3? Please help.

[@ChrisGozzardThatPhysicsGuy]

Because the ratio of Hydrogen Sulphide to Oxygen is 2:3... and we want to know how many moles of Oxygen we need - we just found out how many moles of Hyrogen Sulphide we have...

[@ishwarbhais]

Chris Gozzard Okay Thanks alot!

[@vidhibarot6972]

Parth Shah parth? Is that you?

[@yousrimohammed2667]

Omg the best video ever watched related to calculation. Moles was my miserable part of my life. THANKYOU SO MUCH!!!

[@hollygriffiths9551]

Great video. Thank you

[@ChrisGozzardThatPhysicsGuy]

🤪

[@aaliyahkoledoye4948]

I really liked this video and it helped me a lot. Thank you!

[@rodhaah8931]

why did you divide by 24?

[@ChrisGozzardThatPhysicsGuy]

+Rozi A To convert from mass to moles you must divide by the molar mass of magnesium, which is 24.

[@bobkandijoe]

i thought we're supposed to take the ratio between the product and the resultant?

[@ChrisGozzardThatPhysicsGuy]

Vidip Ganesh Try both methods.. I believe you will get the same answer..

[@bobkandijoe]

but which one is the right one? because in another problem you used the ration between product and reactant, and thanks for the quick reply! Chris Gozzard

[@ChrisGozzardThatPhysicsGuy]

Sorry Vidip Ganesh I think I was confused with your question. I thought you meant where do you apply the ratio. You don't always use the products or the reactants. It depends on what the question is asking you.

[@ChrisGozzardThatPhysicsGuy]

Chris Gozzard Vidip Ganesh for example in the question at 1 min 20 seconds we are only interested in the two reactants.

[@ChrisGozzardThatPhysicsGuy]

Chris Gozzard Vidip Ganesh Are you with me?

[@mariamk4049]

I only everrrr understood stoichiometry from you

[@ChrisGozzardThatPhysicsGuy]

Thanks. That's a nice compliment.

[@ayeshausmanzafar8550]

thank you so much thos helped a lot 💕

[@ChrisGozzardThatPhysicsGuy]

Pleasure!

[@JuliusKhoo]

Mistake in your videos, made me confused as heck. 6:10 that equation, your Mr is 122.5, but since you have two of them, you multiply it by two. This would give you a relative atomic mass of 245g. To find the moles of that, you take mass/Mr = 735/245 which would give you 3moles. Thus, a molecule of oxygen, O2, would have 3/2 moles, as the simplest ratio per molecule is 3/2. So, 3/2 x 3 = 9/2. 9/2 multiplied by the mass of an oxygen molecule, 16+16, would give 32, so 9/2x32=144g, not 288g.

[@ChrisGozzardThatPhysicsGuy]

Hi Julius Khoo I have just double checked the working and I believe you are in error. You are using the 2 infront of the KClO3 twice in your calculation, you only need to use it once - during the ratio calulation between the two sets of moles. I would be grateful if someone on here would independently varify this. Many thanks in advance.

[@JuliusKhoo]

Chris Gozzard Ah, I see now! Boggled my mine for a bit, and yes, you're right! I checked it on : uk.answers.yahoo.com/question/index?qid=20120429002859AAuRn35 too. Thanks for pointing it out!

[@ChrisGozzardThatPhysicsGuy]

Julius Khoo Hey.. No worries. I'm just glad there wasn't a mistake in the video. That would have been a nightmare to do all over again!

[@ishwarbhais]

Mole Ratio is kind of confusing...

[@ChrisGozzardThatPhysicsGuy]

The ratio of Hydrogen Sulphide to Oxygen is 2:3... so to find out how much Oxygen we need we divide by 2 and times by 3..

[@ChrisGozzardThatPhysicsGuy]

Are you with me?? Parth Shah

[@ishwarbhais]

Chris Gozzard Thank you!! :) Understood quite well :)

[@ChrisGozzardThatPhysicsGuy]

Parth Shah Parth it's not easy... It's common for students to slip up with the moles.. It's a very abstract concept..

[@ishwarbhais]

Yes great help :)

[@majedmoradi6628]

thanks aloooooooooooooot

[@ChrisGozzardThatPhysicsGuy]

😄

[@blagultfan]

Mr Chris, How about we leave the studies and teaching behind and start a meth lab together :)) You'll be Walter White and i'll be the less stupid Jesse Pinkman :P

[@ChrisGozzardThatPhysicsGuy]

haha... we'd have to make the physics teacher version..

[@ChrisGozzardThatPhysicsGuy]

there could be a scene where we are trying to balance a car over a cliff and I keep going on about equilibrium of forces and balancing moments.... well maybe..

[@blagultfan]

LMFAO.. Well you do have a great chemistry background as well so it wouldn't be a big issue! I'll get the RV. Heisenberg 2.0 is about to be unleashed XD

[@ChrisGozzardThatPhysicsGuy]

Schrodinger.... thats what I want to be called.. haha