Textbook Problem E9

[505900922]

Could someone help me figure out how to do E9 part a?

[605988349]

For E.9 it is : "Epsom salts consist of magnesium sulfate heptahydrate. Write it's formula.
a) How many atoms of oxygen are in 5.15 g of Epsom salts?"

So, first you need to find the molar mass for the magnesium sulfate heptahydrate. I don't think the professor expects us to have the formula memorized so I searched it up: MgSO4*7H20: which consists of 1Mg: (24.305g/mol), 1S: (32.065g/mol), 11O: (176g/mol) and 14H:(14.1092g/mol) which the molar mass of MgSO4*7H20 would be 246.48 g/mol.

And because the question is asking us to find the atoms of oxygen in a 5.15 g, then we would have to set out the equation as:

atoms of O : (5.15g/246.48g/mol) x (11mol 0 atoms. mol MgHSO4*7H2O) * (6.0221x10^23/1mol)

* we multiply using the Avogadro's number because we are finding the atoms of Oxygen.

which equals to 1.38 x 10^23 atoms of Oxygen.

Hope this helps!

[605988349]

Sorry there's a typo

It should be (11mol 0 atoms/mol MgHSO4*7H2O) instead