Physics 13: Temperature, Kinetic Theory, & the Gas Laws

Question 1

Heat transfer

Answer 1

movement of heat energy from one place or material to another

Question 2

Temperature

Answer 2

what we measure with a thermometer

Question 3

Celsius

Answer 3

temperature scale in which water freezes at 0 and boils at 100

Question 4

Degrees Celsius

Answer 4

unit of the Celsius temperature scale

Question 5

Fahrenheit

Answer 5

most frequently used temp scale in the US; freezing point is 32; boiling point is 212

Question 6

Degrees Fahrenheit

Answer 6

unit of the Fahrenheit temperature scale

Question 7

Kelvin

Answer 7

temperature scale commonly used in science; absolute; 0 in this scale is the lowest possible temp

Question 8

Absolute Zero

Answer 8

lowest possible temperature; temp at which there is no molecular motion

Question 9

Thermal Equilibrium

Answer 9

heat flows from the hotter object to the cooler object until they have exactly the same temp

Question 10

Zeroth Law of Thermodynamics

Answer 10

If 2 systems, A & B, are in thermal equilibrium with each other, & B is in thermal equilibrium with a 3rd system, C, then A is also in thermal equilibrium with C

Question 11

Thermal Expansion

Answer 11

change in size or volume of a given mass with temperature

Question 12

Coefficient of Linear Expansion

Answer 12

alpha, the change in length, per unit length, per 1 degree Celsius change in temp; a constant; depends on the material and to some degree on the temp of the material

Question 13

Coefficient of Volume Expansion

Answer 13

Beta; almost exactly equal to 3 alpha; change in volume, per unit volume, per 1 degree Celsius change in temp

Question 14

Thermal Stress

Answer 14

created by thermal expansion or contraction; can be destructive or useful

Question 15

Ideal Gas Law

Answer 15

PV=NkT; P = absolute pressure of a gas; V is the volume it occupies; N is the # of atoms and molecules in the gas; T is its absolute temp (K)

Question 16

Boltzmann Constant

Answer 16

k; =1.38 x 10^-23 J/K

Question 17

Avogadro’s Number

Answer 17

the actual number of atoms or molecules in 1 mole; = 6.02 x 10^23 mol^-1

Question 18

Thermal Energy

Answer 18

average translational kinetic energy of a molecule (KE); = 1/2mv^2 = 3/2kT

Question 19

PV Diagram

Answer 19

graph of pressure versus volume

Question 20

Critical Point

Answer 20

critical temp above which a liquid cannot exist

Question 21

Critical Pressure

Answer 21

minimum pressure needed for liquid to exist at the critical temp

Question 22

Phase Diagrams

Answer 22

PT graphs; there are well-defined regions on these graphs that correspond to various phases of matter

Question 23

Sublimation

Answer 23

the phase change from solid to gas

Question 24

Triple Point

Answer 24

all 3 curves on the phase diagram meet at this single point, where all 3 phases exist in equilibrium

Question 25

Vapor Pressure

Answer 25

Pressure at which a gas coexists with its solid or liquid phase; created by faster molecules that break away from the liquid or solid and enter the gas phase; depends on both the substance and its temperature; increase in temp increases it

Question 26

Partial Pressure

Answer 26

the pressure a gas would create if it occupied the total volume available

Question 27

Dalton’s Law of Partial Pressure

Answer 27

in a mixture of gases, the total pressure is the sum of partial pressures of the component gases

Question 28

Relative Humidity

Answer 28

tells us how much water vapor is in the air compared with the maximum possible

Question 29

Saturation

Answer 29

maximum humidity (100%); evaporation is inhibited

Question 30

Dew Point

Answer 30

relative humidity is 100%; fog may result from the condensation of water droplets if they are small enough to stay in suspension

Question 31

Percent Relative Humidity

Answer 31

ratio of vapor density to saturation vapor density; = vapor density/saturation vapor density x 100%