Answer:
1. 65.1 kJ; 2. 558 g
Step-by-step explanation:
1.
M_r: 34.08
2H₂S+ SO₂ ⟶ 3S + 2H₂O ; ΔH = -56.9 kJ
Treat the heat as if it were a product in the equation. Then use the molar ratio (56.9 kJ/2 mol H₂S) in the usual way.
Moles of H₂S = 78.0 g H₂S × (1 mol H₂S/34.08 g H₂S) = 2.289 mol H₂S
Amount of heat = 2.289 mol H₂S × (56.9 kJ/2 mol H₂S) = 65.1 kJ
The reaction releases 65.1 kJ of energy.
2.
M_r: 169.87
2AgNO₃ + BaCl₂ ⟶ 2AgCl + Ba(NO₃)₂; ΔH = -345 kJ
Moles of AgNO₃ = 567 kJ × (2 mol AgNO₃/345 kJ = 3.287 mol AgNO₃
Mass of AgNO₃ = 3.287 mol AgNO₃ × (169.87 g AgNO₃/1 mol AgNO₃)
= 558 g AgNO₃
You need 558 g of AgNO₃.
