What thickness (in cm)is the silicon block (density = 2.33 g/cm³)that is 2.87 cm wide and long necessary to react with 91.3 g of Cr₂O₃ by the reaction: 3 Si (s)+ 2 Cr₂O₃(s)→ 3 SiO₂(s)+ 4 Cr (l)? A)2.05 cm B)1.32 cm C)3.08 cm D)8.98 cm E)3.79 cm

Question

Quizplus · Accepted Answer

To find the thickness, first calculate moles of Cr2O3: 91.3 g / 151.99 g/mol = 0.601 moles. From the reaction, 3 moles of Si react with 2 moles of Cr2O3, so 0.601 moles of Cr2O3 require 0.9015 moles of Si. The mass of Si needed is 0.9015 moles * 28.09 g/mol = 25.32 g. The volume of Si is 25.32 g / 2.33 g/cm³ = 10.86 cm³. The thickness is volume / area = 10.86 cm³ / (2.87 cm * 2.87 cm) = 1.32 cm.

What Thickness (In Cm)is the Silicon Block (Density = 2