Suppose 12.0 g of carbon (c) reacts with 70.0 g of sulfur (s) to give 76.0 g of the compound carbon disulfide 1 c s 2 2 . in the process, all the carb

Answer is: mass of unused sulfur is 5.87 grams.

Balanced chemical reaction: C + 2S → CS₂.

m(C) = 12.0 g; mass of carbon.

m(S) = 70.0 g; mass of sulfur.

n(C) = m(C) ÷ M(C).

n(C) = 12 g ÷ 12 g/mol.

n(C) = 1 mol; amount of substance.

n(S) = m(S) ÷ M(S).

n(S) = 70 g ÷ 32.065 g/mol.

n(S) = 2.183 mol.

From chemical reaction: n(C) : n₁(S) = 1 : 2.

n₁(S) = 1 mol · 2 = 2 mol.

Δn(S) = n(S) - n₁(S).

Δn(S) = 2.183 mol - 2 mol.

Δn(S) = 0.183 mol; amount of unused sulfur.

Δm(S) = 0.183 mol · 32.065 g/mol.

Δm(S) = 5.87 g.

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