Answer to Question #152638 in Chemistry for Arvin Shopon

Question

1. Write equilibrium reaction equations for reactions of a state substance

 

(a) Complete combustion of petrol with octane in the petrol, C₈H₁₈.

 

b) Iron (III) sulfide reacts with hydrochloric acid, for example, ferrous chloride and gaseous dihydrogen sulfide are formed.

 

(c) Calcium phosphate is dissolved in dilute sulfuric acid, which forms a precipitate of calcium sulfate and phosphoric acid.

 

Answer 1

Solution:

(a) Complete combustion of petrol with octane in the petrol, C₈H₁₈:

2C₈H₁₈(l) + 25O₂(g) → 16CO₂(g) + 18H₂O(l)

(b) Iron (III) sulfide reacts with hydrochloric acid, for example, ferrous chloride and gaseous dihydrogen sulfide are formed:

Fe₂S₃(s) + 6HCl(aq) → 2FeCl₃(aq) + 3H₂S(g)

Fe₂S₃(s) + 6H⁺(aq) + 6Cl^-(aq) → 2Fe³⁺(aq) + 6Cl^-(aq) + 3H₂S(g)

Fe₂S₃(s) + 6H⁺(aq) → 2Fe³⁺(aq) + 3H₂S(g)

(c) Calcium phosphate is dissolved in dilute sulfuric acid, which forms a precipitate of calcium sulfate and phosphoric acid:

Ca₃(PO₄)₂(s) + 3H₂SO₄(aq) → 3CaSO₄(s) + 2H₃PO₄(aq)

Ca₃(PO₄)₂(s) + 6H⁺(aq) + 3SO₄^2-(aq) → 3CaSO₄(s) + 6H⁺(aq) + 2PO₄^3-(aq)

Ca₃(PO₄)₂(s) + 3SO₄^2-(aq) → 3CaSO₄(s) + 2PO₄^3-(aq)

Answer:

(a): 2C₈H₁₈(l) + 25O₂(g) → 16CO₂(g) + 18H₂O(l)

(b): Fe₂S₃(s) + 6HCl(aq) → 2FeCl₃(aq) + 3H₂S(g)

(c): Ca₃(PO₄)₂(s) + 3H₂SO₄(aq) → 3CaSO₄(s) + 2H₃PO₄(aq)