The options in the question are as follows
a. The motion of particles becomes random.
b. The motion of the particles is unchanged.
c. The particles move with more force.
d. The particles decrease in speed.
Answer:
The particles decrease in speed.
Explanation:
In a gas at room temperature, the particles of the gas move at a very high speed and in a random manner. A gas has no definite volume and it is also assumed that there is minimal interaction between gas particles. Recall that temperature is a measure of the average kinetic energy of the particles of a system. As the temperature is decreased and heat is withdrawn as the CO2 approaches freezing temperature, the speed and kinetic energy of the particles decreases and significant interaction between particles is observed. Hence the CO2 particles slow down.
