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E.9 on homework

Posted: Wed Oct 03, 2018 5:19 pm
by Tatiana 4B
How does one know which coefficient to put in front of the H2O unit when looking at a chemical formula. Ex. In question E9, Epsom Salt has a 7 in front of the H2O, how would we know that?

Re: E.9 on homework

Posted: Wed Oct 03, 2018 5:22 pm
by armintaheri
The question tells you that epsom salt consists of magnesium sulfate heptahydrate. The prefix hepta- means 7. If you weren't given the name of the compound or the chemical formula then you would have no way of knowing the coefficient for water.

Re: E.9 on homework

Posted: Wed Oct 03, 2018 5:22 pm
by Mahir_Hasan2C
Since it says hepta in front of hydrate, where I believe in Greek hepta means 7, we put 7 in front of H20.

Re: E.9 on homework

Posted: Wed Oct 03, 2018 11:41 pm
by joanneyseung22
I am confused about how we would know that O4 is part of magnesium sulfate? Unless I looked it up, I wouldn't have known.
Are there certain suffixes and prefixes that are pertinent to the first exam regarding the review topics? Like -ate, -ite, -ide, etc.

Re: E.9 on homework

Posted: Thu Oct 04, 2018 10:43 am
by Sean Reyes 1J
The prefix "hepta-" implies that there are 7 water molecules.
This would mean that the compound would be written, in its entirety, as:
MgSO4 ・ 7H20