Chemical Energy Flashcards
Endothermic
absorb heat energy from their surroundings
Exothermic
release heat energy to the surroundings
in large scale, what do endothermic reactions need to do
calculate the heat required so the cost for fuel to maintain the correct reaction temperature can be calculated
in large scale, what do exothermic reactions need to do
calculate the quantity of heat released so they know how much heat has to be released to prevent the reaction being too hot
What is the enthalpy of combustion
This is the energy released when one mole of a substance is burned completely in oxygen.
2 formulas to find enthalpy of combustion
Eh = c m deltat
deltaH = Eh / n
Why might results for Eh calculations not be accurate
Heat lost to surroundings, incomplete combustion, alcohol evaporation
Define hess’s law
Law states that the enthalpy change for a chemical reaction is independent of route
Define the bond enthalpy
the energy required to break one mole of a particular bond between a pair of atoms in the gaseous state
Endothermic enthalpy (+ or -)
+
Exothermic enthalpy (+ or -)
-
