True or false? Are these correct?
In a gas kept at a constant temperature, all molecules move with the same speed. FALSE.
A hot object has more thermal energy than a similar cold object only because of greater kinetic energy. TRUE.
3. The thermal energy of the particles in a gas is related to the temperature of the gas. TRUE.
1. and 3. are correct
In #2, it is not the object that has more kinetic energy, it is the atoms and molecules inside the object. This could be interpreted either way. The question is poorly worded.
Not all of thermal energy is associated with molecular and atomic kinetic energy. Part of it is associated with increased average potential energy of molecular vibration and bonding arrangements.
To determine if these statements are correct, we can rely on our understanding of the concepts involved. Let's break them down:
Statement 1: "In a gas kept at a constant temperature, all molecules move with the same speed." - FALSE.
Explanation: According to the kinetic theory of gases, the speed of molecules in a gas varies. The distribution of speeds follows a Maxwell-Boltzmann distribution, where some molecules move faster while others move slower. Thus, keeping the temperature constant does not imply that all molecules will have the same speed.
Statement 2: "A hot object has more thermal energy than a similar cold object only because of greater kinetic energy." - TRUE.
Explanation: Thermal energy is the total energy of the particles in an object due to their motion. In this case, assuming the objects are similar in all other aspects, the hotter object has a greater average kinetic energy of its particles. Since thermal energy encompasses both kinetic and potential energy, the greater kinetic energy contributes to the hot object having more thermal energy overall.
Statement 3: "The thermal energy of the particles in a gas is related to the temperature of the gas." - TRUE.
Explanation: The thermal energy of gas particles is directly related to the temperature of the gas. As the temperature increases, so does the kinetic energy of the particles, resulting in an increase in thermal energy. Temperature is a measure of the average kinetic energy of the particles, so a higher temperature leads to more thermal energy.