The Student Room Group

How to calculate Percentage uncertainty??

Here are the questions:

Calculate the percentage uncertainty associated with the volume of sodium carbonate which you have transferred using a pipette (uncertainty associated with reading a 25cm3 class B pipette is 0.06 cm3)

Calculate the percentage uncertainty associated with your average titre (uncertainty associated with each reading of a 50cm3 class B burette is 0.05cm3) My average titre reading was 23.7
Reply 1
Percentage Uncertainty = (Absolute Uncertainty / Measured Value) x 100

Therefore:

% for pipette = (0.06 / 25) x 100 = 0.24%


% for burette = (0.05 / 23.7) x 100 = 0.21% :biggrin:
Reply 2
yarghan
Reply 3
Original post by Nirgilis
Percentage Uncertainty = (Absolute Uncertainty / Measured Value) x 100

Therefore:

% for pipette = (0.06 / 25) x 100 = 0.24%


% for burette = (0.05 / 23.7) x 100 = 0.21% :biggrin:


Do you not multiply the second one by two (assuming the calculation for average titre was made from two values)? Sorry for re-awakening a 2 year old thread.
Original post by ERdoctor
Do you not multiply the second one by two (assuming the calculation for average titre was made from two values)? Sorry for re-awakening a 2 year old thread.


yes, you do.
Yes you do. (Sorry for re-awaking a 4 years old comment and 6 years old post)
Original post by Ahmed Alfarra
Yes you do. (Sorry for re-awaking a 4 years old comment and 6 years old post)


Thank you for this. (sorry for re-surfacing an 8 year old post and 1 year old comment)
so the equation is going to be

(0.06 / 25) x 100 = 0.24%

(0.05 / 23.7) x 2 x 100 = 41%

(sorry for re-surfacing an 8 year old post and 1 week old comment)

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