SCH4U - Thermochemistry Flashcards
Thermochemistry:
the study of the energy changes that accompany physical or
chemical changes in matter.
Energy:
the ability to do work; SI units joules (J).
Work:
the amount of energy transferred by a force over a distance; SI units joules (J).
Potential Energy (PE or Ep):
the energy of a body or system due to its position or
composition.
Kinetic Energy (KE or Ek):
the energy of an object due to its motion.
Thermal Energy (q):
the total quantity of kinetic and potential energy in a substance.
Heat:
the transfer of thermal energy from a warm object to a cooler object.
Temperature:
a measure of the average kinetic energy of entities in a substance.
Chemical System:
a group of reactants and products being studied.
Surroundings:
all the matter that is not part of the system.
Open System:
a system in which both matter and energy are free to enter and leave the
system.
Closed System:
a system in which energy can enter and leave the system, but matter
cannot.
Isolated System:
an ideal system in which neither matter nor energy can move in or out.
Endothermic:
absorbing energy from the surroundings.
Exothermic:
releasing energy to the surroundings.
Fission:
the process of using a neutron to split a nucleus of high atomic mass into two
nuclei with smaller masses.
Fusion:
the process of combining two or more nuclei of low atomic mass to form a
heavier, more stable nucleus.
Specific Heat Capacity (c):
the quantity of thermal energy required to raise the
temperature of 1 g of a substance by 1 °C; SI units J/(g∙°C).
Calorimetry:
the experimental process of measuring the thermal energy change in a
chemical or physical change.
Calorimeter:
a device that is used to measure thermal energy changes in a chemical or
physical change.
Enthalpy (H):
(H): the total amount of thermal energy in a substance.
Enthalpy Change (ΔH):
the energy released to or absorbed from the surroundings
during a chemical or physical change.
Molar enthalpy change (ΔHr):
the enthalpy change associated with a physical, chemical,
or nuclear change involving 1 mol of a substance; SI units J/mol.
Molar Enthalpy Change of solution (ΔHsol):
the energy released or absorbed per mole
of solute being dissolved in solvent.
Molar Enthalpy Change of Combustion (ΔHc):
the heat released when 1 mole of the
substance undergoes complete combustion with oxygen at constant pressure.
Molar Enthalpy change of vaporization (ΔHv):
the amount of energy needed to change
one mole of a substance from the liquid phase to the gas phase at constant temperature
and pressure.
Molar Enthalpy Change of formation (ΔHf):
the enthalpy change of a chemical reaction
in which one mole of a pure substance is formed from the free elements in their most
stable states under standard state conditions.
Molar Enthalpy Change of Neutralization (ΔHneut):
the energy released per mole of
water formed during a neutralisation reaction.
Potential Energy Diagram:
is the change in enthalpy for 1 mole of compound is formed
from its elements, with all substances at their standard states.
Bond Dissociation Energy:
is the change in enthalpy for 1 mole of compound is formed
from its elements, with all substances at their standard states.
Hessʼs Law:
is the change in enthalpy for 1 mole of compound is formed from its
elements, with all substances at their standard states.
Standard Enthalpy of Formation (ΔHfo):
is the change in enthalpy for 1 mole of
compound is formed from its elements, with all substances at their standard states.
Standard State:
is the change in enthalpy for 1 mole of compound is formed from its
elements, with all substances at their standard states.
Standard State:
is the change in enthalpy for 1 mole of compound is formed from its
elements, with all substances at their standard states.
