Kinetic energy molecular

Kinetic theory A mathematical explanation of the behavior of gases on the assumption that gases consist of molecules in ceaseless motion in space. The molecular kinetic energy depends on the temperature of the gas. 

Fig. 8-4. Effect of temperature on atomic (or molecular) kinetic energy distribution.

A plot of the Maxwell distribution for the same gas at several different temperatures shows that the average speed increases as the temperature is raised (Fig 4.27). We knew that already (Section 4.9) but the curves also show that the spread of speeds widens as the temperature increases. At low temperatures, most molecules of a gas have speeds close to the average speed. At high temperatures, a high proportion have speeds widely different from their average speed. Because the kinetic energy of a molecule in a gas is proportional to the square of its speed, the distribution of molecular kinetic energies follows the same trends. 

At a given temperature, all gases have the same molecular kinetic energy distribution. 

Determine the average molecular kinetic energy and molar kinetic energy of gaseous sulfiar hexafluoride, SFfi, at 150 °C. 

The energies generated by forces among ideal gas molecules are negligible compared with molecular kinetic energies. 

A gas will obey the ideal gas equation whenever it meets the conditions that define the ideal gas. Molecular sizes must be negligible compared to the volume of the container, and the energies generated by forces between molecules must be negligible compared to molecular kinetic energies. The behavior of any real gas departs somewhat from ideality because real molecules occupy volume and exert forces on one another. Nevertheless, departures from ideality are small enough to neglect under many circumstances. We consider departures from ideal gas behavior in Chapter if. 

If you feel the need of a hot cup of coffee, you are going to need to boil some water. Even though there are no obvious physical forces to overcome in this case, you still need a source of energy in order to increase the kinetic energy of the molecules of water. Temperature is a measure of molecular kinetic energy. So you turn on your electric kettle or light your stove burner or whatever to provide the necessary energy. 

Bodies of water at the same temperature have the same average molecular kinetic energies. The volume of the water has nothing to do with its temperature. 

Evaporation and vapor pressure are both explained on a molecular level by the kinetic-molecular theory developed in Section 9.6 to account for the behavior of gases. The molecules in a liquid are in constant motion, but at a variety of speeds depending on the amount of kinetic energy they have. In considering a large sample, molecular kinetic energies follow a distribution curve like that... 

Collisions between molecules or between a molecule and the walls of the container are perfectly elastic, i.e., there is no change in the molecular kinetic energy in a collision. 

What is the ratio of the average molecular kinetic energy of UFg to that of He, both at 300 K ... 

A. The same material is kept in a constant volume, so neither density nor the distance between molecules will change. Pressure will rise because of increasing molecular kinetic energy impacting container walls. 

Effect of Temperature on Surface Tension According to the kinetic theory, molecular kinetic energy is proportional to absolute temperature. The rise in temperature of a liquid, therefore, is accompanied by increase in energy of its molecules. Since intermolecular forces decrease with increase in the energy of molecules, the intermolecular forces of attraction decrease with rise of temperature. 

A is correct. During a phase change, temperature, and thus molecular kinetic energy, is constant. Breaking bonds always absorbs energy. Ice cools things when it melts. 

Kinetic energy is the energy a body possesses by virtue of its motion. It is where m, the body s mass, can be expressed in grams and u, its velocity, can be expressed in meters per second (m/s). The assumptions of the kinetic-molecular theory can be used to relate temperature and molecular kinetic energy (see the Enrichment section, pages 467-469). 

This equation shows that the absolute temperature is directly proportional to the average molecular kinetic energy, as postulated by the kinetic-molecular theory. Because there are molecules in a mole, the left-hand side of this equation is equal to the total kinetic energy of a mole of molecules. 

With this interpretation, the total molecular-kinetic energy of a mole of gas depends only on the temperature, and not on the mass of the molecules or the gas density. 

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