Silicon dioxide reacts with carbon to form silicon carbide and carbon monoxide as shown in the unbalanced reaction below. Determine the percent yield of silicon carbide if 79.1 grams of

Question

carbon reacts with an excess of silicon dioxide and 67.4 g of silicon carbide is actually recovered.

SiO2 + C  → SiC +  CO

Plz help! I am confused and this is due today!

Answer 1

Step 1: Balance the equation

SiO₂ + 3C  → SiC +  2CO

Step 2: Determine the theoretical amount of silicon carbide produced (if all carbon reacted).

Important info:

*"Excess silicon dioxide" tells us carbon is the limiting reactant, and thus the amount of silicon carbide produced depends on how much carbon is available to react.

*Based on the balanced equation, for every 3 moles carbon reacted, 1 mole silicon carbide is produced.

*Molar mass carbon: 12.01 g/mol

*Molar mass silicon carbide: 28.09 g + 12.01 g = 40.1 g/mol

79.1 g carbon x (1 mol carbon / 12.01 g carbon) x (1 mol silicon carbide / 3 mol carbon) x (40.1 g silicon carbide / 1 mol silicon carbide) = 88.04 g silicon carbide

Step 3: Determine the percent yield of silicon carbide

% yield = actual yield / theoretical yield x 100%

= (67.4 g / 88.04 g) x 100%

= 0.766 x 100%

= 76.6%