Amount of heat released? please help?

Suppose 300.0 mL of 1.00 M HCl and 300.0 mL of 1.00 M NaOH, both initially at 23.0�C, are mixed in a thermos flask. When the reaction is complete, the temperature is 29.8�C. uming that the solutions have the same heat capacity as pure water, compute the heat released (in kJ).