Start off by saying lets consider 100 g of rock. Therefore we have
5.0 g Fe2SiO4
7.0 g Mg2SiO4
88.0 g SiO2
lets look at the SiO2. 1 mole of this contains 28 g of Si and 32 g O.
Thus 1 mole or 60 g contains 28 g of Si and 32 g O.
Therefore 88.0 g contains
88.0 g x 28/60 Si = 41 g
88.0 g x 32/60 O = 47 g
Now repeat for the other compounds and add up the masses of each element. Because we chose 100 g to start with then the totals for each element will be the %.
Don't forget to do a check that all the masses add up to 100 g!
A rock is 5.0% by mass fayolite(Fe2SiO4), 7.0% by mass forsterite(Mg2SiO4) and the remainder silicon dioxide. What is the mass percent of each element in the rock?
I have the answers but i don't know how to solve the problem.
How would you in steps solve the problem?
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