Emprical formula of 2.45g of silicon combined with 12.4g cl.

Moles Si = 2.45 / 28.08 g/mol = 0.0873 mol (Grams / Molar Mass)
Moles Cl = 12.4 g / 35.5 g/mol = 0.349 mol (Grams /Molar Mass)

0.0873 / 0.0873 = 1 => Si
0.349 / 0.0873 = 4 => Cl

The Empiral formula is 1:4

The Compound is SiCl4

determines moles of each element:
Si: 2.45 g/28.09 g/mole= 0.087
Cl: 12.4/35.5 g/mole= 0.349
mole ratio: 1 Si: Cl 4
SiCl4

SiCl4