C10 H16(l)+8Cl (g)→10C(s)+16HCl(g) Suppose a chemist runs this reaction and makes569 g of carbon. How many grams of turpentine were consumed?

Method 1 :

Molar mass of C₁₀H₁₆ = (12.0×10 + 1.0×16) g/mol = 136.0 g/mol
Molar mass of C = 12.0 g/mol

C₁₀H₁₆(l) + 8Cl₂(g) → 10C(s) + 16HCl(g)
Mole ratio C₁₀H₁₆ : C = 1 : 10

No. of moles of C made = (569 g) / (12.0 g/mol) = 47.4 mol
No. of moles of C₁₀H₁₆ consumed = (47.42 mol) × (1/10) = 4.74 mol
Mass of C₁₀H₁₆ consumed = (4.74 mol) × (136.0 g/mol) = 645 g


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Method 2 :

Mass of 1 mole of C₁₀H₁₆ = (12.0×10 + 1.0×16) g/mol = 136.0 g/mol
Mass of C in 1 mole of C₁₀H₁₆ = 12.0 × 10 g/mol = 120 g/mol
Mass fraction of C in C₁₀H₁₆ = 120/136.0

Refer to the equation for the reaction. All of the carbon in C₁₀H₁₆ is converted to C(s).
Hence, mass of C₁₀H₁₆ consumed = (569 g) × (136.0/120) = 645 g