Gizmo Warm-up The Boyle’s Law and Charles’ Law Gizmo
shows a container of gas. In the container, the small purple spheres represent molecules. 1. Observe the particles. Are they all moving at the same speed? 2. How do the particles interact with the walls and lid of the container? These interactions contribute to the pressure on the walls of the container. Pressure is defined as force per unit area. The SI units of pressure are newtons per square meter
, or pascals
. 3. Slowly drag the temperature
slider back and forth. (Note: In this Gizmo, the Kelvin scale is used to measure temperature. On the Kelvin scale, 0 degrees is absolute zero, the coldest possible temperature. Absolute zero is equal to
or
) A. How does the change in temperature affect the speed of the molecules? B. How does the change in temperature affect the volume of the container
The Correct Answer and Explanation is:
Correct Answers:
- Are they all moving at the same speed?
No. - How do the particles interact with the walls and lid of the container?
They collide with the walls and lid, exerting force on them.
3A. How does the change in temperature affect the speed of the molecules?
As temperature increases, the speed of the molecules increases.
3B. How does the change in temperature affect the volume of the container?
As temperature increases, the volume of the container increases.
Explanation
The behavior of gas particles in a container is described by kinetic molecular theory and supported by Boyle’s Law and Charles’ Law. In the given Gizmo simulation, small purple spheres represent gas molecules. These molecules do not all move at the same speed. Instead, they move at varying speeds due to differences in kinetic energy. This difference is typical in gases because their motion is random and influenced by collisions with other molecules and the container walls.
When gas molecules collide with the walls and lid of the container, they exert a force over a specific area. This action creates pressure within the container. Pressure results from countless collisions that transfer momentum to the walls. The greater the number or intensity of these collisions, the higher the pressure.
Temperature plays a crucial role in determining the behavior of the gas molecules. According to Charles’ Law, an increase in temperature leads to an increase in the kinetic energy of the molecules. As the temperature rises, the molecules move faster. This increase in speed causes more frequent and forceful collisions with the container walls, which can increase both the pressure and the volume of the gas if the container is allowed to expand.
In the simulation, when the temperature slider is adjusted upward, the gas molecules are observed moving more rapidly. This visual change demonstrates that the kinetic energy and speed of the molecules are directly related to temperature. Additionally, if the container is flexible, an increase in molecular movement causes the volume to expand. This relationship between temperature and volume is explained by Charles’ Law, which states that the volume of a gas is directly proportional to its absolute temperature, provided the pressure is constant.
