thermodynamics

Question 1

thermodynamics

Answer 1

study of heat

Question 1

heat

Answer 1

energy transfer through temperature

Question 2

temperature

Answer 2

average kinetic energy of the motions of a molecule

Question 3

temperature of ideal gas equation

Answer 3

KE= .5mv^2(rms)
v is sqrt of v^2 rms is sqrt(3RT/M)
- t is temp (k)
R is ideal gas constant
M is molar mass

Question 4

kinetic energy and heat equation

Answer 4

KE= 3/2 t*(r/m)
1. kinetic energy is proportional to temperature
2. details of model apply to ideal gases

Question 5

what is kinetic energy measured as

Answer 5

temperature in kelvin

Question 6

system

Answer 6

subset of the universe that is being modeled

Question 7

internal thermodynamic equillibrium

Answer 7

no macroscopic transfers of energy are taking place

Question 8

open systems

Answer 8

exchange matter and energy with sorroundings
- human body is an open system

Question 9

closed system

Answer 9

exchange energy with sorroundings but not matter
- example is a capped test tube

Question 10

isolated system

Answer 10

canNOT exchange matter or energy with sorroundings
- no true insulators in nature

Question 11

state functions

Answer 11

variables like energy, temperature, entropy, gibbs free energy and enthalpy
- pressure, volume, density
- describe state of system without describing how it got there

Question 12

path functions

Answer 12

heat and work
- describe how you got from one equillibrium to another state

Question 13

zeroth law (thermodynamics)

Answer 13

if system A is in equilibrium with system B and C then systems B and C are in thermal equillibrium with each other
- temp

Question 14

Fahrenheit scale

Answer 14

32 F is freezing
bp is 212F
body temp is 98.6

Question 15

celcius scale

Answer 15

body: 37 C
freeze 0 C

Question 16

conversion from celcius to Farenheit

Answer 16

(F-32)*5/9

Question 17

conversion from C to F at high temp

Answer 17

9/5

Question 18

kelvin

Answer 18

0 K= 273 C
K- 273 = C

Question 19

first law of thermodynamics

Answer 19

for closed systems: the total energy change of a system ΔU equals the transfer of energy into the system via heat minus the work performed by the system on its sorroundings
ΔU= Q- W
- comtribition of heat and work

Question 20

work being added to a system

Answer 20

+W

Question 21

work being taken from a system

Answer 21

-W

Question 22

+Δ U

Answer 22

energy is being added to the system

Question 23

• ΔU

Answer 23

energy is being removed from the system

Question 24

+ΔQ

Answer 24

heat is flowing into the system

Question 25

second law of thermodynamics

Answer 25

if two objects are in contact and not in thermal equilibrium, heat will be transferred from high temperature to low temperature - the entropy of an isolated system will increase over time

Question 26

entropy

Answer 26

measure of disorder connected to energy , how much energy is available to do work

Question 27

boltzmann's formula

Answer 27

S = Kb*lnW - s is entropy - kb is constant - w is number of microstates of an observable substance (degrees of freedom)

Question 28

what does an increase in degrees of freedom mean in terms of entropy

Answer 28

increase df increase entropy

Question 29

order the amount of entropy from highest to lowest liquids, solids, gas

Answer 29

solid --> liquid --> gas

Question 30

entropy and work

Answer 30

Δs = q/T

Question 31

can entropy be decreased

Answer 31

yes, but it takes considerable energy (if you break a glass bottle and it shatters it is not easy to piece together)

Question 32

major entropy concepts for MCAT

Answer 32

1. energy will flow from hot to cold items 2. entropy inevitably increases in a true isolated system

Question 33

third law of thermodynamics

Answer 33

at absolute o (0 Kelvin) a crystal structure has an entropy of 0

Question 34

t/f: heat and temperature are different things

Answer 34

TRUE heat is a transfer of energy, temperature is average kinetic energy

Question 35

units of heat

Answer 35

j, calories

Question 36

heat transfer methods

Answer 36

1. conduction 2. convection 3. radiation

Question 37

conduction

Answer 37

two objects with different temperatures touch and heat transfers from hot to cold

Question 38

convection

Answer 38

heat transfer between two objects due to the circulation of fluid - thermal differences due to the densities of fluids

Question 39

radiation

Answer 39

no direct contact - heat transfer via electromagnetic waves

Question 40

thermal expansion

Answer 40

idea that as temperature increases, the object expands

Question 41

exception to thermal expansion

Answer 41

ice is less dense than water and reaches peak density at 4C

Question 42

solid expansion equation

Answer 42

ΔL= alphaL *ΔT - measure change in L - alpha is coefficient of thermal expansion that is specific to substance

Question 43

liquid expansion equation

Answer 43

ΔV = alphav*ΔT

Question 44

ideal gas equation

Answer 44

PV=nRT

Question 45

isothermic system

Answer 45

temp constant on a pressure volume graph

Question 46

adiabatic system

Answer 46

no heat or matter is transferred between a system and its sorroundings - constant entropy - steeper slope than isothermic

Question 47

isobaric

Answer 47

constant presssure