Bismuth oxide reacts with carbon to form bismuth metal: Bi2O3(s) + 3C(s) → 2Bi(s) + 3CO(g) When 775 g of Bi2O3 reacts with excess carbon, (a) how many moles of Bi form? mol Bi (b) how many grams of CO form? g CO

(a) 3.33 mol Bi

(b) 140. g CO

Explanation:

Step 1: Convert 775g to moles

Bi Molar Mass - 208.98 g/mol × 2 = 417.98 g/mol

O Molar Mass - 16.00 g/mol × 3 = 48.00 g/mol

775g Bi₂O₃ ÷ 465.98 g/mol = 1.66316 mol Bi₂O₃

Step 2: Find the conversion from Bi₂O₃ to Bi

1 mole of Bi₂O₃ equals 2 moles of Bi

Step 3: Use Dimensional Analysis

1.66316 mol  ·   = 3.32632 mol Bi

3.32632 mol Bi ≈ 3.33 mol Bi (3 significant figures)

Step 4: Find the conversion from Bi₂O₃ to CO

1 mole of Bi₂O₃ equals 3 moles of CO

Step 5: Use Dimensional Analysis

1.66316 mol  · = 4.98948 mol CO

Step 6: Find molar mass of CO and convert moles to grams

C - 12.01 g/mol

O - 16.00 g/mol

4.98948 mol CO · 28.01 g/mol = 139.775 g CO

139.775 g CO ≈ 140. g CO (3 significant figures)