According to the equation C6H6(I) + 15/2 O2(g) ➞ 6CO2(g) + 3H2O(1), H = -3264.4 KJ/mol, the energy evolved when 7.8 g of lizene is burnt in air will be:

Explanation

To calculate the energy evolved when 7.8 g of benzene (C6H6) is burnt in air, we need to use the given enthalpy change (∆H) and the molar mass of benzene. Given data: ∆H = -3264.4 kJ/mol (the negative sign indicates that the reaction is exothermic, meaning energy is released) Molar mass of C6H6 (benzene) = 78.11 g/mol Step 1: Calculate the number of moles of benzene burnt. Number of moles = mass / molar mass Number of moles = 7.8 g / 78.11 g/mol Number of moles ≈ 0.1 mol Step 2: Calculate the energy evolved for 0.1 moles of benzene. Energy evolved = ∆H × number of molesEnergy evolved = -3264.4 kJ/mol × 0.1 mol Energy evolved = -326.44 kJ The energy evolved when 7.8 g of benzene is burnt in air will be approximately 326.44 kJ. The negativesign indicates that energy is released during the combustion process. Option C is correct.