pnm (chem)

Question 1

Explain why bromine vapour spread upwards until a uniform reddish-brown colouration is seen throughout the gas jars over a period of time

Answer 1

• both air and bromine are made up of tiny particles moving at constant random motion
• the bromine particles diffuse into the spaces between air particles, and vice versa
• when the reddish-brown colour becomes uniform throughout the gas jar, it means that the particles of both gases are evenly spread. a homogeneous mixture of air and bromine is formed

Question 2

why does diffusion in solids take a very long time

Answer 2

particles in the solid are held tgt in fixed positions by strong forces of attraction

Question 3

what is the effect of relative molecular mass on rate of diffusion

Answer 3

lower relative molecular mass –> diffuse faster

Question 4

what is the arrangement of particles in a solid

Answer 4

closely packed in a regular arrangement

Question 5

what is the arrangement of particles in a liquid

Answer 5

closely packed in a random arrangement

Question 6

what is the arrangement of particles in a gas

Answer 6

far apart in a random arrangement

Question 7

what is the forces of attraction between particles of a solid

Answer 7

very strong

Question 8

what is the forces of attraction between particles of a liquid

Answer 8

strong

Question 9

what is the forces of attraction between particles of a gas

Answer 9

negligible

Question 10

what is the movement of particles in a solid

Answer 10

vibrate about fixed positions

Question 11

what is the movement of particles in a liquid

Answer 11

free to move by sliding over one another

Question 12

what is the movement of particles in a gas

Answer 12

move at high speed in all directions

Question 13

what is the kinetic energy of particle in a solid

Answer 13

very low

Question 14

what is the kinetic energy of particle in a liquid

Answer 14

low

Question 15

what is the kinetic energy of particle in a gas

Answer 15

high