Thermodynamics Flashcards
What is the zeroth law of thermodynamics?
when Object A is in thermal equilibrium with Object B, and Object B is in thermal equilibrium with Object C, then Object A and C are also in thermal equilibrium and no net heat flow happens
Temperature
proportional to the average kinetic energy of the particles that make up the substance
Heat
is the transfer of thermal energy from high temp/energy objects to low temp/energy objects (Unit = J)
Thermal Equilibrium
when there is no net heat flow between two objects and they are the same temp
Freezing and Boiling Points in Celsius
0, 100
Freezing and Boiling Points in Fahrenheit
32, 212
Freezing and Boiling Points in Kelvin
273, 373
Absolute Zero
theoretical temperature in which there is no thermal energy. K = 0, F = -460, C = -273
What is the third law of thermodynamics?
the entropy of a perfectly organized crystal at absolute zero is zero
How do you interconvert F and C?
F = 9/5C + 32
How do you interconvert C and K?
K = C + 273
Thermal Expansion
a change in the temperature of most solids results in a change in their length
What is the equation to measure linear thermal expansion?
deltaL = alpha*L*deltaT DeltaL = change in length alpha = coefficient of linear expansion L = original length deltaT = change in temperature
What is a coefficient of linear expansion?
constant that characterizes how a specific material’s length changes the temperature changes. Called alpha, Units = K^-1
What is the equation for volumetric thermal expansion?
deltaV = beta*V*deltaT DeltaV = change in volume Beta = coefficient of volumetric expansion DeltaT = change in temp
What is the coefficient of volumetric expansion?
exactly what it sounds like - constant that characterizes how a specific material’s volume changes as the temperature changes. Called beta, Units = K^-1
What is the relationship between the linear expansion and volumetric expansion coefficients?
beta = 3alpha
Isolated Systems
not capable of exchanging energy or matter with their surroundings so total change in internal energy must be zero; rare in reality
Closed Systems
capable of exchanging energy but not matter with their surroundings
Open Systems
can exchange both matter and energy with the surroundings
State Functions
thermodynamic properties that are a function of only the current equilibrium state of a system. They are independent of that path they take to get to a particular equilibrium state
Ex: pressure, density, temp, volume, enthalpy, internal energy, Gibbs free energy, and entropy
Process Functions
describe the path taken to get from one state to another
Ex: work, heat
First Law of Thermodynamics
states that the change in the total internal energy of a system is equal to the amount of energy transferred in the form of heat to the system, minus the amount of energy transferred form the system in the form of work.
Equation for change in internal energy
deltaU = Q - W deltaU = change in system's internal energy Q = energy transferred into the system as heat W = work done by the system
