we would probably go to the library and study using books and it would be completely normal as we would have nothing to compare it to. and if going to the library and studying with books is more difficult for most people than just going on youtube then the difficulty of exams would probably change to accomodate that. use your brain and dont ask stupid questions you fool
Thank you so much for this video. It was extremely helpful! Just wondering, do we need to know why using larger volumes decreases the % uncertainty, and if so, why does it?
I just came across a question that expected us to know the uncertainty in a burette and then calculate the percentage error. The uncertainty used in the MS was 0.1 . What are the uncertainties that I should know ?
Uncertainty is half the minimum measurement so for a burette will be 0.05. I'm assuming the question you refer to is for a titre which means the uncertainty is doubled as it relies on two burette readings
If measured by a pipette, measuring cylinder or volumetric flask no as there is only one measurement taken. If a titre from a burette then yes as it’s derived from two measurements
You're always given the uncertainty. As a rule of thumb it's always half the minimum measurement of the apparatus e.g. a burette measures to 0.1 cm3 so the uncertainty is 0.05 cm3 etc
The only reason why there is an uncertainty of 0.005 is that we are unsure whether the mass of the pen is 4.395 or 4.385. However, we know (or at least we would assume) that the balance is correct. The zero of a balance is zero, not zero point o o 5(0.005) nor negative zero point o o 5(-0.005), we could argue with the balance's precision (uncertainty) but not accuracy because we don't really have the ability to fix it (at least not in an AS level chemistry class). :)
AASIM AZAM if you have two readings that are within 0.1 of each other then you take those readings, add and divide by 2. If you have more that two readings you have to check that they’re within 0.1 if they are, then add them you divide it by however many are within the 0.1 range
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just wanted to say thanks for your videos. got me an A* at a2 chemistry last year :)
damn thats good. what exam board did you do and what did you use to study chemistry to get the A*?
j.k00 OCR A :)
oh ok. I'm doing Edexcel A2 this year.
what other subjects did you pick?
j.k00 I did biology, chemistry and physics at a2. I got A*A*B respectively. I also got an A in AS geography but dropped it before a2 :)
can i just say, what would we do without youtube.
I hope that means you find the videos helpful :)
we would probably go to the library and study using books and it would be completely normal as we would have nothing to compare it to. and if going to the library and studying with books is more difficult for most people than just going on youtube then the difficulty of exams would probably change to accomodate that. use your brain and dont ask stupid questions you fool
THANK YOU FOR THIS
YOU ARE THE BEST
I'm 100% confident that I am going to pass this percentage error question in my exam😅
Thank you so much for this video. It was extremely helpful! Just wondering, do we need to know why using larger volumes decreases the % uncertainty, and if so, why does it?
To calculate the uncertainty you divide by the amount measured so the bigger that number, the smaller the uncertainty. Hope that makes sense 🤞🤞🤞
@@MaChemGuy Ahhh that makes sense now. Thank you :))
I just came across a question that expected us to know the uncertainty in a burette and then calculate the percentage error. The uncertainty used in the MS was 0.1 . What are the uncertainties that I should know ?
Uncertainty is half the minimum measurement so for a burette will be 0.05. I'm assuming the question you refer to is for a titre which means the uncertainty is doubled as it relies on two burette readings
thank you so much!
Would you double the uncertainty if it was volume?
If measured by a pipette, measuring cylinder or volumetric flask no as there is only one measurement taken. If a titre from a burette then yes as it’s derived from two measurements
saved me thanks!!
Do different measuring tools have standard uncertainties we should have memorized, or will paper 3 always provide us with the error values?
You're always given the uncertainty. As a rule of thumb it's always half the minimum measurement of the apparatus e.g. a burette measures to 0.1 cm3 so the uncertainty is 0.05 cm3 etc
@@MaChemGuy Thank you! So do you recommend memorizing the minimum measurements of different apparatuses?
For the mass, why don't you do 0.005 + 0.005 / 4.39 x100? I thought you had to account for the zero error, and the reading error...
dno did u find out?
The only reason why there is an uncertainty of 0.005 is that we are unsure whether the mass of the pen is 4.395 or 4.385. However, we know (or at least we would assume) that the balance is correct. The zero of a balance is zero, not zero point o o 5(0.005) nor negative zero point o o 5(-0.005), we could argue with the balance's precision (uncertainty) but not accuracy because we don't really have the ability to fix it (at least not in an AS level chemistry class). :)
when you are calculating the mean titre how do you know which value you should leave out in the overall average calculation
AASIM AZAM Should be within 0.1 cm3
If the measurements include more than 2 readings would you times it by the the number of readings or still by 2?
AASIM AZAM if you have two readings that are within 0.1 of each other then you take those readings, add and divide by 2. If you have more that two readings you have to check that they’re within 0.1 if they are, then add them you divide it by however many are within the 0.1 range