Answer : 6.41 moles of silicon are in the sample.
Solution : Given,
Moles of magnesium = 9.62 moles
The given chemical formula for talc is,
From the given chemical formula we conclude that
The stoichiometry of magnesium and silicon is 3 : 2
3 moles of magnesium is equivalent to 2 moles of silicon
9.62 moles of magnesium will be equivalent to moles of silicon
Therefore, the number of silicon present in sample are 6.41 moles.