The standard enthalpy of combustion of solid naphthalene ( C ₁₀ H ₈ ) at 300 K is -5160 kJ mol ⁻¹ . The magnitude of heat released when 1 mole of naphthalene is completely burned in a bomb calorimeter at 300 K is ________ kJ mol ⁻¹ . (Given: R = 25 3 J K ⁻¹ mol ⁻¹ )

Step-by-step solution

The complete combustion of solid naphthalene is given by the balanced chemical equation: C ₁₀ H ₈( s ) + 12 O ₂( g ) 10 CO ₂( g ) + 4 H ₂ O ( l ) The change in the number of moles of gaseous species is: n_g = n_ gaseous products - n_ gaseous reactants = 10 - 12 = -2 The relationship between enthalpy change ( H ) and internal energy change ( U ) is: H = U + n_g RT Rearranging to find the internal energy change (which corresponds to the heat measured in a bomb calorimeter at constant volume): U = H - n_g RT Substitut