Michigan Test for Teacher Certification (MTTC) Secondary Integrated Science Practice test

What can be neglected when considering ideal gas behavior?

1. The forces between gas molecules

2. The volume of the gas molecules

3. The mass of the gas molecules

4. The thermal energy of the gas

The correct answer is: The forces between gas molecules

When considering ideal gas behavior, the assumption is made that the forces between gas molecules can be neglected. This is rooted in the kinetic molecular theory, which implies that gas particles are in constant random motion and that they experience insignificant interactions with one another. The ideal gas law simplifies the behavior of gases by treating them as point particles that occupy no volume and do not exert attractive or repulsive forces. As a result, under most conditions of temperature and pressure, the interactions between gas molecules do not need to be accounted for, allowing for a straightforward application of the ideal gas law. The other options involve factors that do play a significant role in the behavior of gases. The volume of gas molecules, while small compared to the total volume of a gas, cannot be entirely neglected under conditions of high pressure or low temperature when gas molecules are forced closer together. The mass of the gas molecules is critical in understanding the energy and momentum of the gas particles but is not neglected in the ideal gas law. Finally, thermal energy is an essential aspect of gas behavior, as it directly relates to the temperature of the gas and affects the kinetic energy of its molecules. Therefore, neglecting the forces between gas molecules is a fundamental aspect of simplifying complex gas interactions into the ideal gas model