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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: troyquach on September 11, 2019, 01:01:50 AM

Title: Hydrate Lab (AP chem)
Post by: troyquach on September 11, 2019, 01:01:50 AM

Hey guys. I am doing lab tomorrow about an unknown hydrate and was wondering how long I should heat it as we are writing our own procedures. The hydrate is also white and will not change color unlike in Chem year 1 where we had CuSO4 which was blue and turned white. Just a starting guideline time would be great. Thanks!

Title: Re: Hydrate Lab (AP chem)
Post by: chenbeier on September 11, 2019, 01:07:12 AM

Heat it för 2h, cool down then weight, Heat again 1h weight again.  Compare the values. Probably repeat and compare again until constant weight.

Title: Re: Hydrate Lab (AP chem)
Post by: troyquach on September 11, 2019, 02:41:48 AM

If by 2H u mean 2 hours, that might not be applicable in my case just because our class period is 55 minutes. Thanks for the response though!

Title: Re: Hydrate Lab (AP chem)
Post by: Borek on September 11, 2019, 03:29:44 AM

Quote from: troyquach on September 11, 2019, 02:41:48 AM

If by 2H u mean 2 hours, that might not be applicable in my case just because our class period is 55 minutes.

I am afraid that's not enough for any reasonable drying procedure. Actually 55 min. is way too short for most labs I can think of.

What the lab is about? Perhaps you will get dried hydrate?

Title: Re: Hydrate Lab (AP chem)
Post by: Corribus on September 11, 2019, 08:35:50 AM

Depends on sample size. When we do TGA on hydrates they can be de-hydrated in a matter of minutes under dry nitrogen... but this is with samples sizes 25-30 mg.