Question

Tanzanite is used as a gemstone for jewellery. It is a hydrated calcium aluminium
silicate mineral with a chemical formula Ca 2Al xSi yO12(OH).6.H2O. Tanzanite has Mr of 571.5.
Its chemical composition is 14.04 % calcium, 14.17 % aluminium, 14.75 % silicon, 54.59 %
oxygen and 2.45 % hydrogen. (A r values: H = 1.0, O = 16.0, Al = 27.0, Si = 28.1, Ca = 40.1)
What are the values of x and y?

Answer 1

So just to confirm, is this the equation you're using?
\[\Huge Ca_2Al_xSi_yO_{12}(OH)_6H_2O \]
And the given molecular weight is 571.5 grams?

Answer 2

First thing you're gonna need to do is convert each element into moles and then divide by it's smallest molar ratio.