Problem 71 - Chemistry Central Science

Question

What change or changes in the state of a gas bring about each of the following effects? (a) The number of impacts per unit time on a given container wall increases. (b) The average energy of impact of molecules with the wall of the container decreases. (c) The average distance between gas molecules increases. (d) The average speed of molecules in the gas mixture is increased.

Step-by-Step Solution

Answer

(a) To increase the number of impacts per unit time on a container wall, increase the gas pressure, decrease the container's volume, or increase the temperature. (b) To decrease the average energy of impact, lower the gas temperature. (c) To increase the average distance between gas molecules, increase the container's volume or decrease the number of gas molecules inside the container. (d) To increase the average speed of molecules in the gas mixture, increase the gas temperature.

Step 1: a) Increase the number of impacts per unit time on a given container wall.

To increase the number of impacts per unit time on a container wall, we can increase the gas pressure or decrease the container's volume. By doing so, the gas molecules would have a higher possibility of collision, resulting in more impacts on the container wall. However, keep in mind that increasing the temperature would also increase the number of impacts, but at the expense of increasing the average energy of the impacts.

Step 2: b) Decrease the average energy of impact of molecules with the container wall.

The average energy of impact of gas molecules with the container wall is related to the gas temperature. To decrease the average energy of impact, we can lower the gas temperature. Lower temperatures mean that the gas molecules will have less kinetic energy, consequently reducing the energy of the impacts with the container wall.

Step 3: c) Increase the average distance between gas molecules.

To increase the average distance between gas molecules, we can either increase the container's volume or decrease the number of gas molecules inside the container. Increasing the container's volume gives the gas molecules more space for moving, therefore increasing the average distance between them. Decreasing the number of gas molecules would also result in an increase in the average distance between them, as there would be fewer particles interacting.

Step 4: d) Increase the average speed of molecules in the gas mixture.

The average speed of gas molecules is directly related to temperature. To increase the average speed of molecules in the gas mixture, we should increase the gas temperature. An increase in temperature results in an increase of the gas molecules' kinetic energy, which in turn increases their average speed.