Chem: enthalpy and energy profile

what are energy profiles?

show the energy changes that occur during a chemical reaction

what are the two types of energy

chemical and thermal

chemical energy

AKA (enthalpy). It is the energy stored in the bonds of chemical compounds, released or absorbed during a reaction.

what is the symbol for enthalpy?

H, measured in kJ

thermal energy

AKA (heat). kinetic energy that manifests in the speed of moving particlesand is associated with temperature.

what does high thermal energy mean

high thermal energy means that the particles are moving at a faster speed meaning the system has a higher temperature.

activation energy

The minimum energy required to break the bonds for a chemical reaction to occur, allowing reactants to form products. Ea

exothermic reaction

release heat energy to its surroundings causing the temperature of the surroundings to increase. reactants have more energy than the products.

endothermic reaction

absorb heat energy from its surroundings causing the temperature of the surroundings to decrease. In these reactions, the products have higher energy than the reactants.

ΔH

change in enthalpy

+ΔH

indicates an endothermic process where heat is absorbed, leading to an increase in enthalpy.

-ΔH

indicates an exothermic process where heat is released, resulting in a decrease in enthalpy.

what is enthalpy

aka chemical energy is the amount of heat energy absorbed or released by a system during a reaction.

what are energy profiles?

show the energy changes that occur during a chemical reaction

what are the two types of energy

chemical and thermal

chemical energy

AKA (enthalpy). It is the energy stored in the bonds of chemical compounds, released or absorbed during a reaction.

what is the symbol for enthalpy?

H, measured in kJ

thermal energy

AKA (heat). kinetic energy that manifests in the speed of moving particles and is associated with temperature.

what does high thermal energy mean

high thermal energy means that the particles are moving at a faster speed meaning the system has a higher temperature.

activation energy

The minimum energy required to break the bonds for a chemical reaction to occur, allowing reactants to form products. E_a

exothermic reaction

release heat energy to its surroundings causing the temperature of the surroundings to increase. reactants have more energy than the products.

endothermic reaction

absorb heat energy from its surroundings causing the temperature of the surroundings to decrease. In these reactions, the products have higher energy than the reactants.

\Delta H

change in enthalpy

what is enthalpy

aka chemical energy is the amount of heat energy absorbed or released by a system during a reaction.

what is the enthalpy of a endothermic reaction?

positive (+\Delta H).

why is the enthalpy of an endothermic reaction positive?

An endothermic reaction absorbs heat from its surroundings, resulting in an increase in the enthalpy of the system and the products store more energy than the reactants.

what is the enthalpy of an exothermic reaction?

negative (-\Delta H).

why is the enthalpy of an exothermic reaction negative?

An exothermic reaction releases heat to its surroundings, leading to a decrease in the enthalpy of the system as the products have less energy than the reactants.

what is heat of combustion

The heat of combustion is the amount of energy released when a substance is burned in the presence of oxygen, typically measured in joules per mole (\Delta H_c).