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Topic: Doing formula of a hydrate lab... do I round?  (Read 6916 times)

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lenine

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Doing formula of a hydrate lab... do I round?
« on: April 03, 2005, 12:13:07 PM »
Hey,

I'm writing up a lab report for formula of a hydrate--copper(II) sulfate hydrate.

We evaporated it and found the ratio of moles of water to moles of anhydrous copper(II) sulfate.

The thing is the ratio I got from the experiment was 4.80 so the formula would be 5CuSO4.24H2O if I did made a conclusion out of that.

The thing is, the theoretical value is copper(II) sulfate pentahydrate of course. So CuSO4.5H20. I am wondering if I am supposed to round my value up to 5?

Also, if I do round up to 5, how will I justify it in my analysis?


I have sources of error listed in evaluation, but do I just say because of sources of error, I'm rounding it up to 5 or what?


Thanks a lot for your help in advance.


Offline Donaldson Tan

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Re:Doing formula of a hydrate lab... do I round?
« Reply #1 on: April 03, 2005, 03:06:39 PM »
you could carry out error analysis, or suggest improvements to improve the accuracy of your experiment. why not include a background to explain the theory behind the experiment?
"Say you're in a [chemical] plant and there's a snake on the floor. What are you going to do? Call a consultant? Get a meeting together to talk about which color is the snake? Employees should do one thing: walk over there and you step on the friggin� snake." - Jean-Pierre Garnier, CEO of Glaxosmithkline, June 2006

lenine

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Re:Doing formula of a hydrate lab... do I round?
« Reply #2 on: April 03, 2005, 04:08:19 PM »
Yeah, I've listed all the possible errors, and how to improve upon them.

I've also listed how its supposed to work too.

What I'm asking is if I'm supposed to just give my final answer as the 4.8 or round it up to 5 and if I do round how am I suppose to justify that? Just say because its close I rounded it?

Offline Donaldson Tan

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Re:Doing formula of a hydrate lab... do I round?
« Reply #3 on: April 05, 2005, 09:14:45 PM »
round up to 5. firstly, you already know that's the correct answer (so why not?) and you already listed the causes that results in the 0.2 error.
"Say you're in a [chemical] plant and there's a snake on the floor. What are you going to do? Call a consultant? Get a meeting together to talk about which color is the snake? Employees should do one thing: walk over there and you step on the friggin� snake." - Jean-Pierre Garnier, CEO of Glaxosmithkline, June 2006

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