Question

A 0.559-g sample of 9,10-anthracenedione (C14H302) is burned in a bomb calorimeter and the temperature increases from 24.50 °C to 27.50 °C The calorimeter contains 1.15x10g of water and the bomb has a heat capacity of 876J/°C. Based on this experiment, calculate AE for the combustion reaction per mole of 9,10-anthracenedione burned (kJ/mol). C14H2O2() + 15 O2(g)— 14 CO2(g) + 4H2O(1) E k J/mol

Answer 1

For a bomb calorimeter, reaction + bomb + quater = 0 4water = mxCxΔΤ m = mass of water = 1.15x10 g=1150 g C = heat capacity of water = 4.184 J.g-1.0-1 AT = 27.50 – 24.50 = 3.00°C I water = mx C XAT = 1150g x 4.184 J.g?°C1x3.00 °C Awater = 14434.8 J water = 14434.8 ] bomb = Cbomb XAT = 876 J/°C X3.00°C =9bomb = 2628 J Mass of 9,10-anthracenedione = 1g Molecular weight of 9,10-anthracenedione (C4H,02) = 208.21 g/mol Number of moles of 9,10-anthracenedione == mass 0.5599 G=0.002685 mol Mol.wt. 208.21 g/mol Heat of reaction = AE com *0.002685 mol reaction + I bomb + q water = 0 reaction = -(bomb + water) =-(2628+14434.8) J reaction =-17062.8 J =-17.0628 kJ AE com *0.002685 mol =-17.0628 kJ AE comb =-6355.359 kJ/mol Heat evolved per mole =-6.36X 10 kJ/mol