Topic 6 Energetics Flashcards
What is the first Law of thermodynamics
During a chemical reaction, energy cannot be created or destroyed. However, one form of energy can be transferred into another form
What is chemical energy made up of
kinetic energy and potential energy
What is directly proportional to the absolute temperature of a substance
the heat energy of the substance
What is the enthalpy change of a process
the heat energy that is transferred between the system and the surroundings at constant pressure
What is an exothermic reaction
when heat energy is transferred from the system to the surroundings
what is an endothermic reaction
when heat energy is transferred from the surroundings to the system
what does a negative sign indicate
heat energy is transferred from the system to the surroundings. The reaction is exothermic
what does a positive sign indicate
heat energy is transferred from the surroundings to the system
What effect do exo and endo reactions have on temp
exo: increase
endo: decrease
Define standard enthalpy change of reaction
the enthalpy change that occurs when equation quantities of materials react under certain conditions, which is 100 kpa and 298K
How is the change in enthalpy found
H (products) ~ H (reactants)
What is the standard enthalpy change of combustion
the enthalpy change measured at 100kPa and at a stated temperature, usually 298K, when one mole of a substance is completely burned in oxygen
