Thermodynamics

Use thermodynamic data to calculate the standard enthalpy of decomposition of liquid hydrogen peroxide into water and oxygen gas: H2O2(l)-->H2O(g) + 1/2 O2(g). Calculate the energy released by the decomposition of 1.0 g of 90% hydrogen peroxide solution. Molar mass of hydrogen peroxide = 34.0 g/mol. Estimate the final temperature of the product gases of the decomposition. Assume that the constant-volume heat capacities of water and oxygen are respectively 35, and 25 J/mol/K.
enthalpy of H2O2(l) = -187.8 kJ/mol
enthalpy of H20(g) = -241.8 kJ/mol
enthalpy of O2(g) = 0 kJ/mol