Question

Four 0.3 mol samples of xenon gas are described in the table below. Rank these samples in order of decreasing rate of collisions between atoms. That is, select "1" next to the sample with the most collisions per second between Xe atoms and the walls of the container. Select "2" next to the sample with the next most collisions per second between Xe atoms and the walls of the container, and so on. sample volume collisions per second temperature 25. L Choose onel --- 78°C - 113°C 28 L (Choose one B 25. L - 113. °C (Choose one 22. L - 78°C (Choose one D x 5 ?

Answer 1

The ideal gas equation is given as:

PV=nRT

P- pressure

V-volume

n-no. of moles

R- universal gas constant

T- temperature

Also the average kinetic energy of the molecule is given by:

K.E= 2/3 RT

The Kinetic energy of the molecule is proportional to temperature. This means as the temperature is increased , the molecules acquire more kinetic energy (or the energy required for motion) and hence the motion of molecules increases as temperature is increased. Due to increase in motion , there will be increase in collision between molecules and against the walls of the container.

-78^oC is a higher temperature than -113^oC. So the kinetic energy of the molecules will be higher at -78^oC and hence collisions will be more at this temperature.

Now, considering the volume . If the volume of the container is large, that means the molecules have large space available for motion and the chances of collision are less. But if the space is less for them , more collisions take place since their motion is restricted to much closed space.

This collisions are also termed pressure or the force exerted by the molecules per unit area. From the ideal gas equation, PV=NRT

we can rewrite it as , P=NRT/V

So pressure or collision increases with temperature and decreases with volume.

so if we consider molecules at -78^oC , the number of collisions will be more when the volume at this temperature is low.

ie. pressure or collision will be low at 25L than at 22L volume at -78^oC

Hence the order as per the question is given as :

D-1

A-2
C-3
B-4

Answer 2

A= 2

B= 4

C= 3

D= 1