Question

Calculate the net change in enthalpy for the formation of one mole of lead(ii) sulfate from lead, lead(iv) oxide, and sulfuric acid from these reactions. round your answer to the nearest .

Answer 1

ΔHr = -275 kj

Step-by-step explanation:

It is possible to obtain the net change in enthalpy for the formation of one mole of lead(II) sulfate from lead, lead(IV) oxide, and sulfuric acid using the reactions:

(1) H₂SO₄(l) → SO₃(g) + H₂O (l) ΔH=+113kJ

(2) Pb(s) + PbO₂(s) + 2SO₃(g) → 2PbSO₄(s) ΔH=−775kJ

If you sum (1) + ¹/₂(2) you will obtain:

H₂SO₄(l) + ¹/₂Pb(s) + ¹/₂PbO₂(s) → PbSO₄(s) + H₂O(l)

Using Hess's law, the net change in enthalpy for this reaction could be obtained as:

ΔHr = ΔH(1) + ¹/₂ΔH(2)

ΔHr = +113kJ + ¹/₂ -775kJ

ΔHr = -275 kJ