Ap Chem. Ch.5 Flashcards
The study of the relationships between chemical reactions and energy changes involving heat.
Thermochemistry
The study of energy and its transformations
Thermodynamics
Ability to work or transfer heat.
Energy
Energy used to cause and object that has mass to move.
Work
Energy used to cause the temperature of an object to rise.
Heat
Energy of motion
Kinetic energy
Equation for kinetic energy
E = 1/2mv^2
k
Energy an object possesses by virtue of its position or chemical composition.
Potential enery
Joule actually equals…
1 kg(m^2)/s^2
Work equation
F x d
The energy transfered from a hotter object to a colder one.
- deals with the motion of objects
- always flows from hot to cold objects
Heat
States that energy cannot be created or destroyed.
The first law of thermodynamics
The total energy of a system
Internal energy
Changes in internal energy can be measured using this equation.
/_\ E= Ef-Ei
When a system undergoes a physival or chemical change, the change in internal energy is given by the heat added or liberated from the system plus the work done on or by the system. What is the equation?
/_\E= q +w
An endothermic process is one that ________ heat from the surroundings.
Absorbs
An exothermi processs is one that ______heat to the surroundings.
Releases
Depends only on the initial and final states of a system, not by the path by which the system arrived at that state.
A state function
P,V,T,E,H are state fuctions.
Pressure Volume Temperature Internal energy Heat changes at constant pressure
Chemical changes may involve…
-may also involve work done on or by the system
Release of absorption of heat
The heat transfered between the system and surroundings during a chemical reaction carried out under constant pressure.
Enthalpy
The enthalpy change that accompanies a reation is called…
Enthalpy of reaction
Balanced chemical equation that includes states and energy
Thermochemical equation
Enthalpy is an ______ property
Extensive
The /_\ H of enthalpy is _______proportional to the amount of reactant consumed.
Directly
Measurment of heat flow.
Calorimetry
Is an apparatus that measures heat flow.
Calorimeter
The amount of energy required to raise the temperature of an object by 1 degree celsius.
Heat capacity
The heat capacity of 1 g of a substance.
Specific heat
Equation for heat capacity
q=m x c x /_\T
Calculations with constant-pressure calorimetry
m(solution) x c(solution) x /_\T (solution)= - qrxn
If a reaction is carried out in a series of steps, /\H for the reaction is the SUM of /\H for each of the steps.
Hess’s Law
