Energetics Flashcards
Exothermic reaction
A reaction that releases energy to the surroundings
Endothermic reaction
A reaction that takes in energy from the surroundings
How could you use a thermometer to determine whether a reaction is exothermic or endothermic?
See whether temperature increases or decreases during reaction
Energy levels in exothermic reaction
Reactants have more energy stored in their chemical bonds than products
Energy levels in endothermic reaction
Products have more energy stored in their chemical bonds than reactants
Exothermic physical change
Freezing & condensation
Endothermic physical change
Melting & boiling
Examples exothermic reactions
Combustion, Rections of metals with acids, Neutralistaion reactions, Displacement reactions
Examples endothermic reactions
Thermal decomposition
Energy conversion endothermic
Heat energy from surroundings is converted into chemical energy which is stored in the bonds
Enthaply change/Molar enthaply change (delta H)
The amount of heat energy taken in or given out during a chemical reaction. Units: kJ/mol
Positive value enthalpy change
Endothermic (products gained energy)
Negative value enthalpy change
Exothermic (products lost energy)
Activation energy
The minimum amount of energy that particles need to react
