Kinetic theory and gases

Question 1

describe movement of particles in the three states of matter

Answer 1

solid: particles vibrate but they cannot move freely
liquid: particles can move past each other and move around randomly
gas: particles move around very fast and they move all the time. this is because they have a lot of kinetic energy

Question 2

Explain the pressure of a gas in terms of the motion of its particles

Answer 2

particles in a gas are continuously moving in a random way and colliding with the container walls. the force from these collisions produces pressure on the walls. on average the number and force of collisions is the same in all directions, so pressure is the same on all the walls of the container

Question 3

Describe the effect of changing the temperature of a gas on the speed of its particles

Answer 3

as a gas is cooled the average speed of its particles and its volume gets smaller.

Question 4

Describe the term absolute zero, -273°C, in terms of the lack of movement of particles

Answer 4

at absolute zero particles have very little kinetic energy. they are pretty much still.

Question 5

Convert between the Kelvin and Celsius scales

Answer 5

Celsius > Kelvin = add 273 to the Celsius temperature

Kelvin > Celsius subtract 273 from the Kelvin temperature

Question 6

relate the temperature of a gas to the average kinetic energy of a gas molecule

Answer 6

the temperature of a gas is directly proportional to the average kinetic energy of the gas molecules

Question 7

use the relationship:
v1 = v2t1/t2
to calculate volume for gases of fixed mass at constant pressure (rearranging not required)

Answer 7

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Question 8

use the relationship:
v1p1 = v2p2
to calculate volume or pressure for gases of fixed mass at
constant temperature

Answer 8

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Question 9

Use the equation:
initial pressure (pascal, Pa) * initial volume (metre3, m3)
/ initial temperature (kelvin, K) = final pressure (pascal,
Pa) * final volume (metre3, m3) / final temperature
(kelvin, K)

P1V1/T1 = P2V2/T2

Answer 9

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Question 10

describe the use of bottled gases in medicine

Answer 10

in hospitals oxygen and other gases are stored under high pressure in metal bottles or cylinders. this means that the gases take up less room and can be easily stored and transported. when the gas is released from a cylinder its pressure will to atmospheric pressure and it will expand to a much larger volume. the new volume can be calculated using the combined gas equation