[Need Help with Part B]
Given the following analytical data calculate the chemical formula for the two minerals and hence identify the minerals. Values given are in weight percent.

A. Cu=63.3, Fe=11.1, S=25.6
B. SiO$_{2}$=38.0, Al$_{2}$O$_{3}$=21.5, FeO=26.6, MgO=6.3, MnO=7.6
Calculate b) in terms of a formula with 12 oxygens.

Question

[Need Help with Part B]
Given the following analytical data calculate the chemical formula for the two minerals and hence identify the minerals. Values given are in weight percent.

A. Cu=63.3, Fe=11.1, S=25.6
B. SiO$_{2}$=38.0, Al$_{2}$O$_{3}$=21.5, FeO=26.6, MgO=6.3, MnO=7.6
Calculate b) in terms of a formula with 12 oxygens.

jiteshmeghwal9 · Answer

moles of $SiO_2$=0.63
moles of $Al_2O_3$=0.21
moles of $FeO$=0.37
moles of MgO=0.16
moles of MnO=0.11

jiteshmeghwal9 · Answer

Chemical formula $$(SiO_2)_{0.63}(Al_2O_3)_{0.21}(FeO)_{0.37}(MgO)_{0.16}(MnO)_{0.11}$$

jiteshmeghwal9 · Answer

multiply the formula by suitable whole number to convert the subscript into natural numbers

saksh1998 · Answer

you could also easily multiply with 100 as all r to 2 point in decimals and the check of any common number divides them all. that would be more convenient.

legomyego180 · Answer

beautiful, thanks for putting it so simply @jiteshmeghwal9

legomyego180 · Answer

@zepdrix @HolsterEmission something may be incorrect here. Part B is supposed to have 12 oxygens? This formula has only 8

jfraser · Answer

instead of multiplying by lots of numbers to see if you can find a common multiple, I'd try dividing each one by the smallest (0.11) to see if you can find a $small$ whole number ratio instead of a large one