Energy Changes Flashcards
An exothermic reaction ________ heat energy to the surroundings. The overall energy level of the system would hence ________.
releases; decrease
An endothermic reaction ______ heat energy from the surroundings. The overall energy level of the system would hence ________.
gains; increase
ΔH for exothermic reactions is __________.
ΔH for endothermic reactions is __________.
negative; positive
What make up the system of a reaction?
The reactants and products
Name 4 exothermic processes.
- Condensation
- Freezing
- Combustion reactions (hydrocarbon + oxygen —> carbon dioxide + water + heat)
- Neutralisation reactions
Name 5 endothermic processes
- Melting
- Boiling
- Dissolving ionic salts in water
- Thermal decomposition (Using heat to decompose)
- Electrolysis
State the equation for ΔH
Energy absorbed to break bonds + Energy released to form bonds
For an endothermic reaction, energy absorbed for bond breaking < or > energy released from bond forming
>
For an exothermic reaction, energy absorbed for bond breaking < or > energy released from bond forming
Lesser than
