The Student Room Group

A Level Chemistry HELP

Guys,should we discard one of the values of the titres if they are the same?For example,student A achieved titres of values of 27.60 cm3, 27.70 cm3, 27.70 cm3, 27.65 cm3.While calculating the mean titre:
am I supposed to use only one of the values of 27.70 cm3 ? If yes,then why?Because if we used that both of the 27.70 cm3,we would get a slightly different average titre than if we took only one of the 27.70 cm3...
Original post by Anlasan
Guys,should we discard one of the values of the titres if they are the same?For example,student A achieved titres of values of 27.60 cm3, 27.70 cm3, 27.70 cm3, 27.65 cm3.While calculating the mean titre:
am I supposed to use only one of the values of 27.70 cm3 ? If yes,then why?Because if we used that both of the 27.70 cm3,we would get a slightly different average titre than if we took only one of the 27.70 cm3...

If none of the titres are specified to be from the rough titration, you use all of them, since they are all concordant (i.e within 0.10 cm^3 of each other).

As such:

mean titre = (27.60 + 27.70 + 27.70 + 27.65)/4 = 27.66 cm^3 (2 dp)

Supposing one of the titres was from the rough titration, you would discard it. Because of the order in which you’ve written the titres, I would assume that the rough titre would be 27.60 cm^3.

If 26.60 cm^3 is the rough titre:

mean titre = (27.70 + 27.70 + 27.65)/3 = 27.68 cm^3 (2 dp)
Reply 2
Original post by TypicalNerd
If none of the titres are specified to be from the rough titration, you use all of them, since they are all concordant (i.e within 0.10 cm^3 of each other).

As such:

mean titre = (27.60 + 27.70 + 27.70 + 27.65)/4 = 27.66 cm^3 (2 dp)

Supposing one of the titres was from the rough titration, you would discard it. Because of the order in which you’ve written the titres, I would assume that the rough titre would be 27.60 cm^3.

If 26.60 cm^3 is the rough titre:

mean titre = (27.70 + 27.70 + 27.65)/3 = 27.68 cm^3 (2 dp)

Thanks for clarifying!
But I have a question.Are concordant values within 0.20 cm3 of each other or 0.10 cm3 of each other?
Original post by Anlasan
Thanks for clarifying!
But I have a question.Are concordant values within 0.20 cm3 of each other or 0.10 cm3 of each other?

Depends on your exam board.

If you do Edexcel, I’m fairly sure it’s within 0.20 cm^3 of each other (I should really remember this as it was the course I did last year lmao).

I’m fairly certain every other exam board says within 0.10 cm^3 of each other.
Reply 4
Original post by TypicalNerd
Depends on your exam board.

If you do Edexcel, I’m fairly sure it’s within 0.20 cm^3 of each other (I should really remember this as it was the course I did last year lmao).

I’m fairly certain every other exam board says within 0.10 cm^3 of each other.


Yeah,I'm doing Edexcel.But in a question of a book,there was these values ,24.15 cm3.24.30 cm3,25.60cm3,26.80cm3.In the answer booklet,it was written that there was no concordant values here.But isn't 24.15cm3 and 24.30 cm3 concordant of each other,if we take concordant values to be within 0.20 cm3 of each other?(In the book,it was written that concordant values are "generally" considered to be within 0.20 cm3 of each other.)
Original post by Anlasan
Yeah,I'm doing Edexcel.But in a question of a book,there was these values ,24.15 cm3.24.30 cm3,25.60cm3,26.80cm3.In the answer booklet,it was written that there was no concordant values here.But isn't 24.15cm3 and 24.30 cm3 concordant of each other,if we take concordant values to be within 0.20 cm3 of each other?(In the book,it was written that concordant values are "generally" considered to be within 0.20 cm3 of each other.)

Then there’s probably a mistake in the textbook.

I’d assume the mistake is that there was perhaps a typo made when the titres were written out, so it should read in such a way that there are no concordant titres.
Reply 6
Original post by TypicalNerd
Then there’s probably a mistake in the textbook.

I’d assume the mistake is that there was perhaps a typo made when the titres were written out, so it should read in such a way that there are no concordant titres.


Oh! I get it now! Thank you so much for taking the trouble to clarify the confusions!

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