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# Having trouble with chemistry watch

1. hi,

when you are performing a titration, you obviously use a burette... if u fill the burette up to the top , meaning fully , up to the last line.. is the initial burette reading 50 or 0... assuming that it is a 50cm3 burette... also after u hav titrated some volume out of it... which way do u read the burette..? from the bottom upwards, or from upwards to downwards..??
2. If the burette says 0 at the top, then it's zero. When you're done you just read off the volume bottom upwards.
3. It's better to not fill it right to the top but if it is filled to the top the initial volume is 50, then you take a final reading eg. 40 and the average titre is 10.
If you did it the other way round eg, 0 and 10, it wouldn't make any difference to your results.
4. Initial reading is 0, but the volume would be 50.

Once you've titrated some volume out, you read the scale on the side of the burette and simply take the reading.
5. thanks guyss.. so say i used the initial burette reading to be 50 would the final burette reading be from bottom upwards or the other way round.. sorry to sound confusing??? and y shudnt u fill all the way to the top ..?
6. you can fill it all the way to the top if you wish, but you might not always need 50cm3 - this is why some people only fill it a certain amount. If you're getting a bit confused with it though, fill it upto 50 cm3.
I always say the initial burette reading is 50 (assuming I fill it to the top) and then say after you have done your titration, the final burette reading is 40, your titre is 10cm3.
To find the average titre - find the difference between the initial burette reading and the final burette reading.
I hope this is helpful!
7. so say the miniscus lies between 24 and 25... if am reading from the bottom to top it will be 25.5 but if i read top down it wil be 24.5....... this is what am cnfused abt which one do i do ?!
8. Protip: Please don't say 0, but say 0.00!
9. thanks bt can sum1 answer ma question pleaseeeeeeee
10. (Original post by ben10)
so say the miniscus lies between 24 and 25... if am reading from the bottom to top it will be 25.5 but if i read top down it wil be 24.5....... this is what am cnfused abt which one do i do ?!
No, 25.5 is between 25 and 26, not 24 and 25.
11. oh i get it am being stupid it dosent matter which way u read it
12. Say if you've completely filled the burette, up to 50cm3, then your initial reading will be 0.00
But say your first titre was 19.7cm3 i.e. that's how much of say e.g. potassium manganate was needed, that means the volume of the potassium manganate used is 19.7cm3. Say now for your 2nd trial you don't want to fill the entire burette up again, then your initial reading is 19.7cm3. Say then your final burette reading for that was 39.30cm3, i.e. reading downwards, then your volume of potassium manganate used is 19.60cm3 because 39.30 - 19.7 = 19.6cm3

Remember you can stop your titration when you have reached two readings within 0.1cm3 of each other!
13. (Original post by ben10)
oh i get it am being stupid it dosent matter which way u read it
Be sure to read to the nearest 0.05 mL. If the bottom of the meniscus lies between two lines (assuming the burette is graduated every 0.1 mL) you need to take the reading bearing that in mind.
14. thankyou are u doing A2 chemistry?
15. (Original post by Phenylethylamine_)
Say if you've completely filled the burette, up to 50cm3, then your initial reading will be 0.00
But say your first titre was 19.7cm3 i.e. that's how much of say e.g. potassium manganate was needed, that means the volume of the potassium manganate used is 19.7cm3. Say now for your 2nd trial you don't want to fill the entire burette up again, then your initial reading is 19.7cm3. Say then your final burette reading for that was 39.30cm3, i.e. reading downwards, then your volume of potassium manganate used is 19.60cm3 because 39.30 - 19.7 = 19.6cm3

Remember you can stop your titration when you have reached two readings within 0.1cm3 of each other!
thankyou are u doing A2 CHEM?
16. (Original post by ben10)
thankyou are u doing A2 CHEM?
Np Yup
17. really? lol

anyway just make up the results
thats how you get an A*

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Updated: March 18, 2011
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