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Topic: Molecular mass?  (Read 1947 times)

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Offline naturelover

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Molecular mass?
« on: October 25, 2014, 07:22:55 AM »
I have a silly question regarding this question:

"How many grams of iodine (I2) are formed from the oxidation of an excess of an excess of Kl by 6g of K2Cr2O7, under acid conditions?"

My question is why is K2Cr2O7=  294.2g?

Why is it 294.2g? How did you calculate it? i only got 142....
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Offline Arkcon

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Re: Molecular mass?
« Reply #1 on: October 25, 2014, 07:43:39 AM »
Nope, 294 it is.  If you show us your work, we'll tell you where you went wrong.  Although more likely, by typing it in, it will occur to you first. ;)
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Hey, I'm not judging.  I just like to shoot straight.  I'm a man of science.

Offline naturelover

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Re: Molecular mass?
« Reply #2 on: October 25, 2014, 09:29:04 AM »
yep sure! So I checked the table for molecular mass.. so since K= 19 (x2 because there's 2 of it), Cr=24 (x2), O=8 (x7).

So if I times and add all these up it'll be:: 38+48+56=142

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Offline Borek

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Re: Molecular mass?
« Reply #3 on: October 25, 2014, 09:35:40 AM »
You are mistaking atomic number for atomic weight.
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Offline naturelover

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Re: Molecular mass?
« Reply #4 on: October 25, 2014, 09:48:23 AM »
aha! thank you!!! I got the correct answer now!!!.. silly me!
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