Endothermic and Exothermic Processes - AP Chemistry

A process that requires continuous external energy input. Thermodynamically unfavorable without energy input.

1 atm pressure and 298 K temperature. Reference conditions for thermodynamic measurements.

Combustion is an exothermic reaction. Burning reactions always release energy.

Energy cannot be created or destroyed, only transformed. Conservation of energy principle in thermodynamics.

Rusting of iron is exothermic. Oxidation reactions release energy.

A process that occurs without external energy input. Thermodynamically favorable under given conditions.

$\triangle H$ is negative. Energy is released during the reaction.

$\triangle H$ is positive. Energy is absorbed during the reaction.

The sign of $\triangle H$ is negative. Heat release means negative enthalpy change.

Photosynthesis is an endothermic process. Light energy is absorbed to drive the reaction.

Enthalpy is the total heat content of a system. It's a state function measuring internal energy.

It is an endothermic process. Dissolution breaks ionic bonds, absorbing energy.

$\triangle H = 150 - 200 = -50$ kJ. Products have lower energy than reactants.

Melting is endothermic. Energy is needed to break intermolecular forces.

The sign of $\triangle H$ is positive. Heat absorption means positive enthalpy change.

The minimum energy required to initiate a reaction. Energy barrier that must be overcome.

A calorimeter measures the heat of chemical reactions. Device that quantifies energy changes in reactions.

The heat absorbed or released during a chemical reaction. Energy change when reactants become products.

Heat is absorbed by the system. System gains energy from surroundings.

Evaporation of alcohol is endothermic. Phase change requires energy input.

Lighting a match is exothermic. Combustion of match head releases energy.

Boiling water is an endothermic process. Energy is required to overcome intermolecular forces.

1 atm pressure and 298 K temperature. Reference conditions for thermodynamic measurements.

Combustion is an exothermic reaction. Burning reactions always release energy.

The system is the part of the universe being studied; surroundings are everything else. Defines boundaries for energy transfer analysis.

The minimum energy required to initiate a reaction. Energy barrier that must be overcome.

Freezing water is an exothermic process. Energy is released as molecules form ordered structure.

$\triangle H$ is positive. Energy is absorbed during the reaction.

The sign of $\triangle H$ is negative. Heat release means negative enthalpy change.