Kinetic Model of Matter

Question 1

Shape of Solid

Answer 1

Fixed

Question 2

Shape of Liquid

Answer 2

Not fixed

Question 3

Shape of Gas

Answer 3

Not fixed

Question 4

Volume of Solid

Answer 4

Fixed and incompressible

Question 5

Volume of Liquid

Answer 5

Fixed and incompressible

Question 6

Volume of Gas

Answer 6

Not fixed, compressible and occupies volume of container

Question 7

Arrangement of molecules in solid

Answer 7

Closely together with little space, arranged in a regular pattern

Question 8

Arrangement of molecules in liquid

Answer 8

Slightly further apart with little space in between molecules, arranged in a disorderly manner

Question 9

Arrangement of molecules in gas

Answer 9

Far apart with mainly empty spaces between molecules

Question 10

Motion of molecules in solid

Answer 10

Constantly and randomly vibrating about fixed position as it is held in place by strong attractive forces between the particles

Question 11

Motion of molecules in liquid

Answer 11

Constantly and randomly moving to and fro within the liquid, sliding over each other.

Question 12

Motion of molecules in gas

Answer 12

Moving constantly and randomly with high speed, colliding with each other and with the walls of the container due to the little attractive forces between the particles

Question 13

Observation for Brownian Motion

Answer 13

Bright specks of light moving about in a constant, random motion.
The smaller air particles are in constant, random motion. The air particles collide unevenly with the larger smoke particles and exert a resultant force on the smoke particles. The smoke particles move in the direction of the resultant force due to Newton’s Second Law of Motion.

Question 14

Effect of Temperature on Molecular Motion

Answer 14

At higher temperature, the air particles collide with the smoke particles with a larger force and more frequently. The motion of smoke particles is faster and more random.

Question 15

Pressure of gas in terms of motion of its molecules

Answer 15

The gas particles are in a constant, random motion, moving freely within the container. They collide and rebound from the walls of the container. This is due to a resultant force acting on the gas particles by the walls of the container. Hence, since pressure is the force acting per unit area, gas pressure is thus caused due to collisions of the gas particles with the walls of the container.

Question 16

Relationship between pressure and temperature of gas

Answer 16

For a fixed mass of gas at a constant volume, as the temperature increases, the average kinetic energy of the particles increases hence the speed of the particle increases, the particle will bombard the walls of the container with a larger force and more frequently, this results in the force per unit area exerted by the gas particles on the walls to increase, this cause the pressure of the gas to increase.
The temperature of the gas measured in kelvin is directly proportional to the pressure of the gas.

Question 17

Relationship between volume and temperature of gas

Answer 17

For a fixed mass of a gas at constant pressure, as the temperature of the gas in the container increases, the average speed of the particles increases, and the particles bombard the walls more frequently and with a larger force. This causes the pressure of the gas to increase. However, as the gas pressure is larger than atmospheric pressure, a net force acts on the container causing the volume to increase. As the volume of gas increases, the gas pressure decreases until it is equal to the atmospheric pressure.

Question 18

Relationship between pressure and volume of gas

Answer 18

For a fixed mass of a gas at constant temperature, the average speed of the gas particles is the same. If the volume of the container is increased, the number of gas particles per unit volume in the container will be decreased. The frequency of collisions with the walls of the container will also decrease due to the increase in volume. Hence the pressure exerted by the gas will decrease. The force of collisions remains the same as the average speed of the gas particles remains constant. Therefore, for a fixed mass of gas at constant temperature, the pressure of a gas is inversely proportional with its volume.