Sydney T. answered • 05/06/16
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Molarity is moles over liter so to do this problem you would need to convert 7.8g of MgCl into moles. Then you would need to convert the 725mL to Liters.
To convert Grams to moles dived 7.8g MgCl by the total mass of the compound which is 59.775
7.8/59.775 =.1305
After that convert the 725mL - Liters
to do that divide the 725 by 1000
so you end of getting .725
the last step is putting it all together so .1305moles MgCl/.725Litters
If you need any more help let me know!
R. Kevin B.
If the actual compound was MgCl2, which it should be, the molar mass is 95 g/mol. The original question looks like it was written incorrectly because MgCl does not exist--the charges don't add to zero since Mg2+ and Cl1- would give an actual formula of MgCl2. When the correct formula is used and the correct molar mass is used, then the answer becomes, 7.8 g * (1 mol / 95g) / 0.725 L = 0.113 M MgCl2 (aq).10/28/19