Unit Three: Energy Changes and Rates of Reactions Flashcards
Thermodynamics
The study of energy and energy transfer.
Thermochemistry
The study of the energy that is involved in chemical reactions.
Law of Conservation of Energy
The law stating that the total energy of the universe is constant.
Temperature (T)
A measure of the average kinetic energy of the particles that make up a substance or system.
Enthalpy (H)
The total kinetic energy and potential energy of a substance.
Enthalpy Change ( ΔH)
The difference between the enthalpy of the reactants and the enthalpy of the products in a reaction.
Exothermic Reaction
A reaction that results in a net release of energy.
Enthalpy of Reaction ( ΔHrxn)
.
Standard Enthalpy of Reaction ( ΔH°rxn)
The enthalpy change associated with a reaction that occurs at SATP
Thermochemical Equation
A balanced chemical equation that indicates the amount of energy absorbed or released by the reaction it represents.
Endothermic Reaction
A reaction that results in a net absorption of energy.
Mass Defect
The difference in mass between a nucleus and its nucleons
Nuclear Binding Energy
The energy that is associated with the strong force holding a nucleus together; accounts for the mass defect.
Nuclear Fission
A reaction in which a heavy nucleus splits into lighter nuclei.
Nuclear Fusion
A reaction in which two smaller nuclei fuse to form a larger nucleus.
Specific Heat Capacity (c)
A measure of the amount of heat that is needed to raise the temperature of 1 g of a substance 1°C or 1 K.
Heat Capacity (C)
The amount of energy that is needed to raise the temperature of an object 1°C or 1 K.
Coffee-Cup Calorimeter
A calorimeter that consists of two nested polystyrene cups (coffee cups) sitting in a 400 mL beaker.
Constant- Pressure Calorimeter
A calorimeter (such as a coffee-cup calorimeter) that is open to the atmosphere.
Hess’s law of heat summation
The scientific law stating that the enthalpy change of a physical or chemical process depends only on the beginning conditions (reactants) and the end conditions (products) and is independent of the pathway of the reaction or the number of intermediate steps in the reaction.
Formation Reactions
A reaction in which a substance is formed from elements in their standard states.
Standard molar enthalpy of formation 🔼H•f
The quantity of energy that is absorbed or released when 1 mol of a compound is formed directly from its elements in their standard states.
Non-renewable resource
Resources that will run out ; once the supply is used up, there will be no more.
Renewable Resource
Resources that exist in infinite supply.
Instantaneous Rate
The rate of a reaction at a particular time; can be determined by drawing a tangent to a concentration-time curve at the given time and finding the slope of the tangent.
Rate Law Equation
And equation that describes the rate of a reaction by the concentration of the reactants raised to an exponent, ex: Rate= k[A]m[B] n
Rate Constant (k)
A proportionality constant ; different for each reaction at any given temperature.
Second order Reaction
A reaction in which the overall reaction order is 2
Initial Rates method
A method for measuring and comparing the initial rates of reactions
Half Life, t1/2
The time that is needed for the mass or concentration of a reactant to decrease by one-half of its initial value.
Collision Theory
The theory stating the reacting particles (atoms, molecules, or ions) must collide with one another for a reaction to occur.
Activation Energy, Ea
The minimum energy that is required for a successful
