thermal physics Flashcards

Question

what does a (volume or pressure) vs temperature graph look like from the ideal gas laws?

Answer 1

straight line (through origin in Kelvin or intercept x at -273 in degrees)

Answer 2

at constant volume, the pressure of an ideal gas is directly proportional to its absolute temperature p1/T1=p2/T2

Answer 3

the sum of the masses of all the atoms that make up a single molecule

Answer 4

the sum of the relative atomic masses of all the atoms making up a molecule

Answer 5

the number of atoms in 12g of carbon 12. gives the number of atoms in any volume of substance who's mass in grams is the same as its relative atomic mass

Answer 6

the mass that one mole of the substance would have and is equal to its relative atomic or molecular mass.

Answer 7

the mass of one mole is often twice their relative masses because many gases exist as molecules which are more than two atoms bonded together.

Answer 8

(p1 x v1) /T1 = (p2 x v2) /T2

Answer 9

pV = nRT V= volume p= pressure n= number of moles R= molar gas constant T= temperature in K

Answer 10

the gas constant for one molecule of gas

Answer 11

work must be done so there must be a transfer in energy.

Answer 12

the energy transferred to change the volume of the gas (the work done)

Answer 13

1) say molecule Q is moving towards wall A with velocity u 2) assuming the collisions are perfectly elastic, the wall pushes back on the molecule when it hits the wall causing it to rebound in the opposite direction with momentum -mu 3) change in momentum is 2mu 4) assume Q has no collisions with other molecules, time between collision of Q and A is (2 x length) /u. 5) number of collisions per second is therefore u/ (2 x length) so rate of change in momentum is 2mu x (u/ (2 x length)) 6) force= rate of change of momentum N2 Law so force exerted on the wall by one molecule is (2mu^2) / (2 x length)= (mu^2) / length 7) Q is one of many so total force of all molecules on wall A= m(u^2+u^2+...) / length 8) mean squared speed is then (u^2+u^2+...) / N 9) put into equation before to get F=(Nm x mean squared speed) / length 10) pressure = force/area so p= (Nm x mean squared speed) / V 11) treat all N molecules the same so c^2= 3 mean squared c^2 12) pV= 1/3 (Nm x mean squared speed)

Answer 14

there will be more collisions between the molecules and the walls of the container in a given amount of time. on average, collisions will result in larger changes in momentum and exert a larger force on the walls of the container.

Answer 15

if the volume is larger, there will be a longer time between molecule-wall collisions so the rate of change of momentum causing an decrease in force on the walls of the container as the volume increase, SA of the walls increases, so increasing the area stops the pressure from increasing.

Answer 16

all molecules of a gas are identical. the gas contains a large number of molecules. the molecules have negligible volume compared to the volume of the container. the molecules continually mover around randomly. the motion of the molecules follow newtons laws collisions between molecules themselves or at walls of a container are perfectly elastic. molecules move in straight lines between collisions the forces that act during collisions last for much less time than the time between collisions

Answer 17

a gas that obeys the assumptions in kinetic theory model

Answer 18

in the form of kinetic energy

Answer 19

use pV= nRT and pV= 1/3 (Nm x mean squared speed) equate formulas and then multiply by 3/2

Answer 20

mass= molar mass/ Avogadro's constant

Answer 21

fewer atoms means less collisions per second. average momentum change per collision stays constant so total momentum change decreases as less collisions occur.

Answer 22

The volume/size of the gas molecules is negligible/point mass or point molecule Or molecules are point masses Or small compared to the volume/size occupied by of the gas

thermal physics Flashcards

(48 cards)