energetics 5.2 Flashcards
what is the enthalpy change of a reaction
the heat energy it releases or absorbs per mole
what is the unit for enthalpy change
kJ/mol
what does breaking bonds do
absorbs energy (endothermic)
what does making bonds do
releases energy (exothermic)
how are enthalpy changes displayed
energy level diagram
what happens in an endothermic reaction
heat is absorbed, products end up with more energy than the reactants had
what happens in an exothermic reaction
heat is released, the products end up with less energy than the reactants had
what is calorimetry
an experimental method to measure enthalpy change
Q=
mcΔT
ΔH=
-Q/moles
specific heat capacity of water
4.18J/g/oC
what is combustion calorimetry
combusting a fuel to heat up the water
significant sources of error in combustion calorimetry
heat loss
incomplete combustion
what is solution calorimetry
reaction measured happens dissolved in water
spices of error in solution calorimetry
no longer pure water (changes shc)
