How many moles of copper are present in a sample of tennantite with a mass of 2290 grams?

18.58 moles of Cu

Solution:

Data Given:

Chemical Formula of Tennantite = Cu₁₂As₄S₁₃

Mass of Cu₁₂As₄S₁₃ = 2290 g

M. Mass of Cu₁₂As₄S₁₃ = 1479.06 g. mol⁻¹

Step 1: Calculate Moles of Cu₁₂As₄S₁₃ as,

Moles = Mass : M. Mass

Putting values,

Moles = 2290 g : 1479.06 g. mol⁻¹

Moles = 1.548 mol

Step 2: Calculate Moles of Cu,

As,

1 mole of Cu₁₂As₄S₁₃ contains = 12 moles of Cu

So,

1.548 mol of Cu₁₂As₄S₁₃ will contain = X moles of Cu

Solving for X,

X = (1.548 mol * 12 mol) : 1 mol

X = 18.58 moles of Cu