Question

When reading a buret, where is the initial and final volumes taken from? The top (where the zero is) or the bottom?
If the buret is completely full, is my initial volume 0?

Answer 1

if buret is full than yes your initial volume is 0 and when you release some volume you read the final volume under initial. keep in mind that your initial volume doesnt have to be 0, it can be for example 5 cm3 and when you release lets say 5 cm3 you will read 10 cm3 where you spent 5 cm3 in total. i hope you get what i am trying to say.

Answer 2

Im asked to record my burette readings so I will have to have at least have 3 experiments in total,can all of my initial burette readings be zero? Thank you so much.

Answer 3

they can but it wastes time cause you can "move" your zero, example:
first titration V0=0 cm3 -> V1=10 cm3
second titration V0=10 cm3 -> V2=19 cm3 ( V2=9 cm3)
third titration V0=19 cm3 -> V3= 30 cm3 (V3= 11 cm3)

Answer 4

In my practical exam,do I need to record,in the sense put it in a table,for the rough titration which is usually asked in the first question

Answer 5

im not sure what you are trying to say... rough titration?

Answer 6

oh i googled it :D
no you dont keep record of rough titration cause you are doing it just to know in real titration when to slow down with release of titrant cause equivalence point is near.

Answer 7

Thank you so much (:

Answer 8

no problem

Answer 9

Hi again! I'm asked to record my burette readings now repeating it for 2 more times which makes it a 3 in total.They've asked me write down the volume of FA2(in the question) also.is this volume same for every repetitive experiment?

Answer 10

could you elaborate what FA2 is

Answer 11

fa2 is 0.150 moldm-3 NaOH

Answer 12

that is the volume of NaOH which you released so yes it should be the same with certain degree of deviation

Answer 13

in other words you write the volume of every titration

Answer 14

I thought moldm-3 is concentration !?

Answer 15

you have written: "They've asked me write down the volume of FA2(in the question) also.is this volume same for every repetitive experiment?" so you have asked about the volume, which you should write down but concentration is always the same, it doesnt change with volume

Answer 16

Im a little confused,so what will be the volume of fa2 added?

Answer 17

the volume you released in the flask

Answer 18

If you don't mind,can you have a look at may June 2011 paper 3 variant 1 AS level,I'm doing that paper right now . Thank you.

Answer 19

can you give me a link or something... im from croatia so i dont know what you mean by June 2011 paper 3 variant 1 AS level... :D

Answer 20

Hehe sure http://www.xtremepapers.com/papers/CIE/Cambridge%20International%20A%20and%20AS%20Level/Chemistry%20(9701)/9701_s11_qp_31.pdf

Answer 21

I pretty much need guidance with the entire paper and it would be awesome if you could guide me through since my real exam is tomorrow :)

Answer 22

oh i see now, so you must record rough titration also, so you write the rough titration volume that's easy.
next, you write in those boxes all released volumes by which i mean you take one flask of FA3 and titrate with FA2 and after color change you write in the first box volume that you spent, take second flask repeat the procedure and write also the spent volume and so on... it should look like this example:
1 | 5,0 mL
2 | 4,8 mL
3 | 5,1 mL
and so on if you are doing more than three titrations...
then 1 (b) you take average value of your volumes (here on my university we must write average volume with standard deviation ex. 5 +/- 0,1 mL
and 1 (c) is the calculation...

Answer 23

now when im looking at your papers i see how nice and easy you have it :D we have to make all that by ourselves :D

Answer 24

I wish I had found it easy like u did :(

Answer 25

But anyways,I didn't really understand the table part

Answer 26

i wrote one too many of reports so ones like you have are pretty much childs play :D

Answer 27

If I don't do it ur way,can I just make 4 rows and columns writing on my left the final burette reading followed by initial burette reading and then the volume of NaOH added? All of my initial reading would be zero and NaOH added would be 25 cm3 where as the final is according to what value i get which will vary a little but lesser than the rough titre. Did I get it right?

Answer 28

pretty much but 25 cm3 is the full volume of burette so your volume will be less. but generally you got the idea...

Answer 29

But it's Kay if I write all of em as 25 rite

Answer 30

if i got right what you are trying to say yes it ok

Answer 31

I'm sorry but this is kinda new for me!

Answer 32

its alright nobody is born with all the knowledge and skill

Answer 33

Conclusion,the only thing that'll vary in the table is the final burette reading,correct?

Answer 34

(:

Answer 35

yes correct

Answer 36

Hi ! I have another doubt based on the same question paper

Answer 37

and what is exactly your doubt?

Answer 38

Calculation part 3 and 4

Answer 39

so that points 3 and 4 are your goal, i mean goal of the exercise. so you calculated concentration of diluted solution now you need to calculate concentration of original sample. c1*V1=c2*V2

Answer 40

I'm sorry but is there an easier way?

Answer 41

i dont know what is hard, you just need to play with simple equations, if you have volumes ill calculate it for you...

Answer 42

I'll try doing it again ... And thank you :D

Answer 43

I have a doubt in this paper , could u help me http://www.xtremepapers.com/papers/CIE/Cambridge%20International%20A%20and%20AS%20Level/Chemistry%20(9701)/9701_w08_qp_2.pdf

Answer 44

what exactly is your doubt

Answer 45

Question 5 part c 3 and 4

Answer 46

??