DeltaH Flashcards
What does a negative ΔH indicate?
A negative ΔH indicates an exothermic reaction, meaning energy is released to the surroundings.
What does a positive ΔH indicate?
A positive ΔH indicates an endothermic reaction, meaning energy is absorbed from the surroundings.
In an exothermic reaction, is ΔH written on the left or right side of the reaction?
ΔH is written on the right side because energy is released as a product.
In an endothermic reaction, is ΔH written on the left or right side of the reaction?
ΔH is written on the left side because energy is absorbed as a reactant.
In an exothermic reaction, is the enthalpy arrow pointing up or down?
The enthalpy arrow points down because the system loses energy.
In an endothermic reaction, is the enthalpy arrow pointing up or down?
The enthalpy arrow points up because the system gains energy.
Is combustion exothermic or endothermic?
Combustion is exothermic because it releases energy as heat.
Is photosynthesis exothermic or endothermic?
Photosynthesis is endothermic because it absorbs energy from sunlight.
Does bond breaking release or absorb energy?
Bond breaking absorbs energy and is endothermic.
Does bond forming release or absorb energy?
Bond forming releases energy and is exothermic.
What happens to the surroundings in an exothermic reaction?
The surroundings get warmer because heat is released.
What happens to the surroundings in an endothermic reaction?
The surroundings get cooler because heat is absorbed.
Example: Is freezing water exothermic or endothermic?
Freezing water is exothermic because it releases heat to the surroundings.
Example: Is boiling water exothermic or endothermic?
Boiling water is endothermic because it absorbs heat to change state.
What sign (+/-) does ΔH have for an exothermic reaction?
ΔH has a negative (-) sign for exothermic reactions.
