How do gas particles behave in a container and adding more gas to a fixed container have on the pressure and temperature of the gas?
Adding more gas to a fixed container at constant temperature increases the pressure, while adding more gas at constant volume increases the temperature.
Gases are composed of a large number of particles that behave like hard, spherical objects in a state of constant, random motion. These particles move in a straight line until they collide with another particle or the walls of the container. As the gas molecules collide with the walls of a container the molecules impart momentum to the walls, producing a force perpendicular to the wall. The sum of the forces of all the molecules striking the wall divided by the area of the wall is defined to be the pressure. The particles of a gas move in straight-line motion until they collide with another particle or with one of the walls of its container. Collisions between gas particles and between particles and the container walls are elastic collisions. An elastic collision is one in which there is no overall loss of kinetic energy. When molecules of gas come in contact with either each other or with the walls of the container, they exert pressure. Since they cannot escape the container, they bounce around and strike the inside wall of the container. When a gas is compressed, gas particles move closer to each other. Hence, collisions per unit area increase. In other words, they collide with the walls of the container more frequently. This leads to an increase in pressure on the container of the wall. If you heat a gas you give the molecules more energy so they move faster. This means more impacts on the walls of the container and an increase in the pressure. Conversely if you cool the molecules down they will slow and the pressure will be decreased. When a gas is heated, its molecules start moving at a much faster speed and this consequently causes an increase in pressure within the container holding the gas. If the container is not strong enough, the activity of the gas molecules is likely to cause it to burst. Gas pressure is the force exerted by gaseous molecules as they collide with the walls of their container. If the volume and temperature of a container of gas are held constant, an increase in the number of gas particles will result in an increase in pressure, and vice versa. An increase in the number of gas molecules, while container volume stays constant, increases pressure. A decrease in container volume increases gas pressure. An increase in temperature of a gas in a rigid container increases the pressure. This can be easily understood by visualizing the particles of gas in the container moving with a greater energy when the temperature is increased. This means that they have more collisions with each other and the sides of the container and hence the pressure is increased. An increase in the number of gas particles in the container increases the frequency of collisions with the walls and therefore the pressure of the gas. The last postulate of the kinetic molecular theory states that the average kinetic energy of a gas particle depends only on the temperature of the gas. When the temperature of the container increases, the kinetic energy of the gas molecule becomes high. This means the collision rate of the particles increases. Due to the collision of gas particles, the pressure increases across the wall of the container.
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