ATAR Notes: Forum

VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Chemistry => Topic started by: dekoyl on December 25, 2008, 01:02:29 pm

Title: Knowledge of experimental process/errors
Post by: dekoyl on December 25, 2008, 01:02:29 pm

Are we required to know (ie. will we be examined on) possible errors in experiments?

For example, a question asks "Explain why NaOH should not be left standing in a glass burette." The answer says that NaOH reacts with the silica in the glass which reduces the accuracy of the experiment.

Thanks.

Title: Re: Knowledge of experimental process/errors
Post by: shinny on December 25, 2008, 01:13:58 pm

There are some errors you should know in unit3 chemistry, particularly with NaOH being hydroscopic and titration/gravimetric errors etc. That error however, I have personally NEVER seen.

Title: Re: Knowledge of experimental process/errors
Post by: dekoyl on December 25, 2008, 01:23:48 pm

Thanks shinny.

Quote from: shinny on December 25, 2008, 01:13:58 pm

There are some errors you should know in unit3 chemistry, particularly with NaOH being hydroscopic

Hmm is that covered in the Heinemann book? I haven't flicked through every single page, but scanning the index, I don't think it's there.

Title: Re: Knowledge of experimental process/errors
Post by: shinny on December 25, 2008, 01:27:09 pm

It was in the Nelson one...not sure about Heinemann.

Title: Re: Knowledge of experimental process/errors
Post by: Mao on December 26, 2008, 08:55:36 pm

I think the main problem would be NaOH reacting with CO2 from the atmosphere, hence never leave it sitting in the open ever...