Thermochemistry!. AP Chapter 5. Temperature vs. Heat. Temperature is the average kinetic energy of the particles in a substance. Heat is the energy that is transferred from one object to another. Heat always flows from the hotter object to the colder object. Energy!.
AP Chapter 5
1 calorie will raise the temperature of 1 g of H2O from 14.5 °C to 15.5 °C.
1 calorie is equal to 4.184 Joules (exactly!)
ΔE = Efinal - Einitial
Initial state refers to the reactants, while final state refers to the products.
A system composed of H2 (g) and O2 (g) has greater internal energy than a system composed of H2O (l).
Gases have greater kinetic energy and must lose some of that energy to change states back to the liquid state.
Internal energy is a function of state.
In an endothermic system where it absorbs heat, ∆H will be positive (∆H > 0).
In an exothermic system, where heat is given off, ∆H will be negative (∆H < 0).
Also refer to Appendix C!