Question E9 Outline 1

[405963118]

Can someone explain how to get the formula of magnesium sulfate heptahydrate? The question asks to write the formula and i do not recall how to get the formula from just the words. Clearly there’s magnesium and sulfate but what does hepta hydrate stand for? H plus what?

[Kristy Sun 3L]

Hello!

For magnesium sulfate heptahydrate, magnesium would be Mg and sulfate would be SO4. Hepta stands for 7 and hydrate stands for water, so it would be MgSO4 + 7H2O. I'm pretty sure Dr. Lavelle said that we won't be required to know this for the midterm, and we will be going over naming compounds later in the quarter.

Hope this helps!

[Isaac 14B]

Magnesium sulfate:
We know that this molecular compound, commonly known as Epsom salt, involves the interactions between Magnesium ions and Sulfate ions. Through memorization, which we will be going over later in the quarter, we know that Mg has a charge of +2 and Sulfate has a charge of -2. To form a neutral compound, we would need to compare the charges. Thankfully, they just so happen to cancel out, leaving us with a combined form of MgSo4.

Heptahydrate:
We will learn prefixes and suffixes later in the quarter I believe. Hepta is the prefix indicating seven and hydrate as a molecular term indicates water, so we will have 7 H2O molecules along with our salt. This leaves us with...

Mg(So4)(H2O)7

*numbers included in this post should be read as subscripts!