Calculate the molecular weight, wt.% element in a crust and wt.% oxide in a crust for the given information below.
SiO2
Molecular weight of SiO2 = (Si atomic weight + 2*O atomic weight)
= (28.09 + 2*16.00) g/mol
= 60.09 g/mol
In Earth's crust, Si is present in the form of SiO2 (quartz). Therefore, the wt.% of Si in the crust can be calculated as follows:
To calculate wt.% of Si in SiO2:
Si atomic weight = 28.09 g/mol
Total molecular weight of SiO2 = 60.09 g/mol
% Si = (Si atomic weight / Total molecular weight of SiO2) * 100
% Si = (28.09 / 60.09) * 100
% Si = 46.76%
Therefore, the wt.% of Si in a crust is approximately 46.76%.
To calculate the wt.% of oxide:
Since SiO2 is an oxide compound, the wt.% of oxide is simply 100%, as SiO2 is 100% oxide by weight.