Answer:
The heat energy released from the reaction is approximately 51.4791 kJ
Step-by-step explanation:
The given parameters are;
The heat of the reaction of 2Cl (g) → Cl₂ (g) = -243.4 J
The given mass of Cl being converted to chlorine gas, Cl₂ = 15.0 g
From the reaction for the heat of formation, we have;
2 moles of chlorine produces 1 mole of Cl₂ to release 243.4 kJ of energy per mole of Cl₂
The mass of 1 mole of Cl ≈ 35.453 g
Therefore, from number of moles, n = Mass/(Molar Mass), we have;
The number of moles of chlorine, in 15.0 g of chlorine = 15.0/35.453 ≈ 0.423 moles
Therefore, given that 2 moles of Cl produces 1 mole of Cl₂, we have;
0.423 moles of Cl will produce 0.423/2 ≈ 0.2115 moles of Cl₂
The heat energy released from the reaction is therefore, H ≈ 0.2115 × 243.4 kJ = 51.4791 kJ.