Hess Flashcards
(7 cards)
1
Q
Equation for ΔH
A
(enthalpy of products) - (enthalpy of reactants)
2
Q
Enthalpy of reactants:
Enthalpy of products:
A
bonds broken
bonds formed
3
Q
Exothermic:
Endothermic:
A
making bonds, negative
breaking bonds, positive
4
Q
Limitations of hess cyle
A
- using average bond enthalpies so actual value will be slightly different depending on the environment
- reactions may not be standard as all of the reactants and products may not be in their standard states
5
Q
Formation data
A
arrows up
products - reactants
6
Q
Combustion data
A
arrows down
reactants - products
7
Q
Why can a reaction be exothermic
A
more energy released from forming bonds than required to break them
