If you are needing at least 100. grams of HCI to be produced, how many
grams of SiCl4 is t needed? *
SiCl4(l)
+
_
H2O(l)
——
SiO2 (s)
+
HCl(aq)

116.4 g of SiCl4

Explanation:

SiCl4(l) +2H2O(l) > SiO2 (s) + 4HCl(aq)

Given this balanced reaction equation which will serve as a guide for our work, we can now look at the stoichiometry of the reaction.

Number of moles of HCl needed = mass of HCl/ molar mass of HCl

Molar mass of HCl= 36.46 g/mol

Number of moles of HCl= 100/36.46 g/mol= 2.74 moles

From the balanced reaction equation;

1 mole of SiCl4 yields 4 moles of HCl

x moles of SiCl4 will yield 2.74 moles of HCl

x= 2.74/4 = 0.685 moles of SiCl4

Therefore mass of SiCl4= number of moles of SiCl4 × molar mass of SiCl4

Mass of SiCl4= 0.685× 169.9 g/mol = 116.4 g of SiCl4