1. Thermochemistry By: Kyle B. Joey G.

2. What is Thermochemistry? Thermochemistry is the study of the heat evolved or absorbed in chemical reactions. It is concerned with the heat exchange accompanying transformations, such as mixing, phase transitions, chemical reactions and so on.

3. definitions  Heat is the transfer of energy from an object of higher energy to an object of lower energy  Heat is symbolized by the letter q  The system is the object your concentrating on  The surrounding is everything else

4. Endothermic vs. Exothermic Delta H (∆H) is the change in temperature If Delta H is positive, the reaction is endothermic and absorbs heat energy If Delta H is negative, the reaction is exothermic and releases heat

5. Hess’s Law This is the heat exchange accompanying a transformation is the same whether the process occurs in one or several steps.

6. “System” & “Surroundings” The system regarded as the reaction products and reactants, whereas the surroundings consist of everything else in the universe

7. Coffee cup calorimeter c m ∆T= q c is the specific heat capacity (J/g°C) m is the mass (g) ∆T is the change in temperature (°C) q is the heat (J)

8. “Bomb” calorimeter q=c ∆T C=specific heat capacity of the “bomb” calorimeter (J/gCelcius) ∆T=change in temperature (degrees C)

9. Specific Enthalpy Definitions Enthalpy- the total heat of a system. Enthalpy Change-(∆H) The difference in Enthalpy between the initial state and the final state. (∆H=H products –H reactants ) Its equal to “q” when all the change in energy is heat energy.