Thermochemistry (Calorimetry)
Thermochemistry is the study of the energy changes that occur during chemical reactions.
Energy
Energy is the capacity to do work or transfer heat.
Types of energy:
Kinetic energy
Potential energy
Heat
Heat is the transfer of energy between objects due to a temperature difference.
Heat flow:
Endothermic reactions
Exothermic reactions
Enthalpy
Enthalpy is the heat content of a system at constant pressure.
Enthalpy change:
ΔH = H(products) - H(reactants)
Exothermic reactions (ΔH < 0)
Endothermic reactions (ΔH > 0)
Calorimetry
Calorimetry is the measurement of heat flow in a chemical reaction or physical process.
Types of calorimeters:
Coffee cup calorimeter
Bomb calorimeter
Hess's Law
Hess's Law states that the enthalpy change of a reaction is independent of the pathway between the initial and final states.
Hess's Law calculations:
Enthalpy of formation
Enthalpy of combustion
Thermochemical Equations
Thermochemical equations show the enthalpy change of a reaction.
Key features:
Stoichiometric coefficients
Enthalpy values
Spontaneity and Entropy
Spontaneous reactions occur without external intervention.
Entropy is a measure of the disorder or randomness of a system.
Gibbs free energy:
ΔG = ΔH - TΔS
Spontaneous reactions (ΔG < 0)
Bond Energies
Bond energy is the energy required to break a bond.
Bond energy calculations:
Bond breaking
Bond forming
Thermochemistry is the study of the energy changes that occur during chemical reactions.
Energy
Energy is the capacity to do work or transfer heat.
Types of energy:
Kinetic energy
Potential energy
Heat
Heat is the transfer of energy between objects due to a temperature difference.
Heat flow:
Endothermic reactions
Exothermic reactions
Enthalpy
Enthalpy is the heat content of a system at constant pressure.
Enthalpy change:
ΔH = H(products) - H(reactants)
Exothermic reactions (ΔH < 0)
Endothermic reactions (ΔH > 0)
Calorimetry
Calorimetry is the measurement of heat flow in a chemical reaction or physical process.
Types of calorimeters:
Coffee cup calorimeter
Bomb calorimeter
Hess's Law
Hess's Law states that the enthalpy change of a reaction is independent of the pathway between the initial and final states.
Hess's Law calculations:
Enthalpy of formation
Enthalpy of combustion
Thermochemical Equations
Thermochemical equations show the enthalpy change of a reaction.
Key features:
Stoichiometric coefficients
Enthalpy values
Spontaneity and Entropy
Spontaneous reactions occur without external intervention.
Entropy is a measure of the disorder or randomness of a system.
Gibbs free energy:
ΔG = ΔH - TΔS
Spontaneous reactions (ΔG < 0)
Bond Energies
Bond energy is the energy required to break a bond.
Bond energy calculations:
Bond breaking
Bond forming