OpenStax Chapter 5 Key Terms Flashcards
thermochemistry
study of the heat absorbed or released during chemical and physical changes
work
process of causing matter to move against an opposing force
potential energy
the energy that an object has because of its relative position, composition, or condition
kinetic energy
energy that an object possesses because of its motion
thermal energy
kinetic energy
associated with the random motion of atoms and molecules
exothermic process
releases heat
system gets colder, surroundings get warmer
endothermic process
absorbs heat
system gets warmer, surroundings get colder
temperature
quantitative measure of “hot” or “cold”
K, C, F
calorie
amount of energy required to increase the temperature of one gram of water 1 C
joule
amount of energy used when a force of 1 N moves an object one meter
heat capacity
quantity of heat (q) absorbed or released by a body of matter when it experiences a temperature change of 1 C
extensive
specific heat
quantity of heat required to raise 1 gram of a substance by 1 C
intensive
molar heat capacity
quantity of heat required to raise 1 mol of a substance by 1 C
calorimetry
method for measuring the amount o heat transferred to or from a substance
system
the substance or substances undergoing the chemical or physical change
surroundings
all other matter, including components of the measurement apparatus, that serve to either provide heat to the system or absorb heat from the system
chemical thermodynamics
study of the relationship between heat, work, and other forms of energy involved in the
internal energy
state function
energy associated with particles of the substance
depends on the state of the system
U = q + w
expansion/pressure-volume work
expansion work
P𝚫V=-w
if work is done on the system, 𝚫V = -
if work is done by the system 𝚫V = +
state function
depends only on the state of the system and not how the state is reached
enthalpy
sum of the system’s internal energy (U) and the system’s pressure-volume work
H = U + PV
cannot be directly measured, so instead measure the change in enthalpy at constant pressure
extensive
standard state conditions
1 atm, 1 M, 25 C
enthalpy of combustion
enthalpy change when one mole of a substance burns under standard state conditions
reactants - products
enthalpy of formation
enthalpy change for a reaction in which exactly one mole of a pure substance formed from free elements in their most stable form under standard state conditions
Hess’s Law
if a process can be written as a sum of the several stepwise steps, the enthalpy change of the total process equals the sum of the enthalpy changes of the steps
heat of reaction
equal to the enthalpy under constant pressure
