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Is there space lessons?
Hi Seoyeon,
Please elaborate more about your question. Are you referring to Astronomy and Cosmology?
Best regards,
Chemistry Department
Hi,Ive been struggling with stoichometry and organic chemistry a lottt?so if you had any websites that would be really helpful for me to improve itd be amazing.And if it was for coordinated sciences 0654 then even better!!!
Dear Saanvi,
Thanks for reaching us!
Stoichiometry allows us to predict the outcome of a reaction or else to determine how reactants need to be engaged to yield any particular amount of products. The difficulties faced in solving stoichiometric problems can be overcome by having a clear and correct understanding of the mole concept, balancing chemical reactions, finding the limiting reagent, and mastering problem-solving strategies. You can definitely improve the latter by practicing! Use these as keywords to find more related questions (or websites), and practice more! If there’s any concept that you cannot understand or any step that you find hard, feel free to write to us. We are more than happy to help you! You can also try the past paper questions, which are more structured and relevant.
Four general steps of solving a stoichiometric problem:
1. Write the balanced equation
2. Find the number of moles of the given substance (this can be either a reactant or a product, according to your question)
3. Find the molar ratio to calculate the number of moles of the wanted substance (The correct balanced equation should accompany this step.
Therefore, you shouldn’t have a hard time balancing a chemical equation.)
4. Convert moles of the wanted substance into desired units according to your question (Eg: grams)
For Organic Chemistry, you can try making a short note or writing the reactions on a paper until you are thorough with that. Online video tutorials, too, can help you.
We hope this helps!
We believe that “where there’s a will, there’s a way!”. So keep being focused! All the best!
Best Regards,
Chemistry Department
thankyou so much!!
Dear Saanvi,
We are always here to help you!
Best Regards,
Chemistry Department
Hi there, my question is in reference to paper 0620/43/m/j/18, Q no 6 part c iii); why does HClO3 disassociates in water as H3O+ and ClO3-, instead of H+ And ClO3-. Also, can u tell me which acids and alkalis partially disassociates and fully disassociate to form ions? Also in 0620/63/m/j/18,Qno 3part e), can the answer be ester instead of fuel as they r also colourless, pleasant smelling and burn with blue flame.
Thank you
Nawalamir
Hi Nawalamir,
Thanks for reaching us, we are happy to help you!
As you have mentioned it is true that HCLO3 dissociates into H+ and CLO3-, when you completely forget or ignore the aqueous solution. In reality, when the hydrogen cation (H+) is released into water it will be bound to a water molecule through a coordinate covalent bond and forms H3O+. This H3O+ ion is called the hydronium cation. In the acid-base chemistry, both H+ and H3O+ are interchangeable. But, for 0620/43/m/j/18, Q no 6 part c iii) the answer has to be H3O+ since H2O is given on the left-hand side of the equation and the equation has to be balanced. In case if you write H+ the equation will not be properly balanced.
Strong acids (HCl, HNO3, H2SO4, HCLO3, HCLO4, etc) and bases (KOH, NaOH, Ba(OH)2, etc), fully dissociate whereas weak acids (CH3COOH – acetic acid, H2C2O4 – oxalic acid, etc) and bases (ammonia, pyridine, etc) partially dissociate.
Yes, for 0620/63/m/j/18, Q no 3 part e) you will be given marks for writing either fuel or an organic compound.
Hope this helps! We are here for you!
Best Regards,
Chemistry Department
Are all the IGCSE past exam papers to be purchased. I previously downloaded some of their past papers from for free and i really hope those ones are not bogus. is their one particular place i am supposed to download the past exam papers from and are all others websites concerning this fake.
Hello there,
You may download past exam papers here: https://igcsecentre.com/cambridge-igcse-past-exam-papers/. They are updated until the March 2020 series. Furthermore, there’s no purchase needed to download the past papers.
Thank you.
Are you still posting these free lessons. if yes, then i have already subscribed to it. how do i get informed on when these videos are going to be published.
Hello Treasure,
Once you subscribe to our newsletter you will be notified for the upcoming schedule of our online lessons and Q&A sessions.
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