IGCSE/GCSE/O & A Level/IB/University Student Forum

Qualification => Subject Doubts => GCE AS & A2 Level => Sciences => Topic started by: sweetie on April 13, 2010, 04:26:30 pm

Title: CIE CHEM. PRACTICALS
Post by: sweetie on April 13, 2010, 04:26:30 pm

HEY PPL, cud any1 ans my 2 que.

 what does it mean when dey say:

1." measure the vol. from the  burette to 0.05 cm³" AND IF IT MEANS TO 2 d.p then how do we do it for a burette calibrated at 0.1cm³ intervals?????

2.  measure temperature to da nearest 0.01^0C???????

Title: Re: CIE CHEM. PRACTICALS
Post by: tmisterr on April 13, 2010, 05:32:39 pm

well it could be that they mean it as accuracy/uncertainty. Most schools, including mine use burettes that have the smallest reading as 1cm³ but as you know uncertainty of an instrument is the least reading divided by two, which is +/-0.05cm³ so what they mean is that they want to record to that uncertainty, But just ask the practical teacher at your school to be sure.

the temperature one i am not sure exactly, maybe someone else has any ideas??

Title: Re: CIE CHEM. PRACTICALS
Post by: sweetie on April 13, 2010, 06:04:22 pm

newayz, thanx 4 da help 


in this specimen paper,  when we draw da table , for the temp of FA1  before the first  addition of FA2 the temp will be for eg.24 ,  and after the first addition its 32

, so will we consider this 32 as the initial for the second addition or we still take 24 as the initial temperature???

Title: Re: CIE CHEM. PRACTICALS
Post by: tmisterr on April 13, 2010, 06:45:40 pm

take 24 as initial temperature for each addition