Tutor profile: Edwin D.
Subject: Physical Chemistry
Specify and analyze critically the assumptions that underlie the kinetic model of gases.
• The gas consists of molecules of mass constantly moving in random motion obeying the laws of classical mechanics, which means they move in linear motion. • The size of the molecules is negligible, in the sense that their diameter is much smaller than the average distance traveled between collisions. • The molecules interact through brief elastic collisions. This means that there is no loss in the total translational kinetic energy with the collisions and no other interaction between them. • The average kinetic energy of all molecules is proportional to the absolute temperature of the gas. This means that any gas at equilibrium will have the same kinetic energy, however, not necessarily the same speed. • The volume of all the molecules is negligible compared to the gas’s total volume.
Explain how the perfect gas equation of state arises by the combination of Boyle’s law, Charles’s law, and Avogadro’s principle
The combination of Boyle’s law (p α 1/V), Charle’s law (V α T) and (p α T) with a fixed mass quantity of gas provides the relationship of PV α T. Then, combine with Avogadro’s (n α V) it gives PV α nT→pV=nRT in which R is the constant of proportionality found experimentally for all gases.
Subject: Basic Chemistry
Explain how the compression factor varies with pressure and temperature and describe how it reveals information about intermolecular interactions in real gases.
This (Z) factor is the ratio of the measured molar volume of a gas if it behaved like an ideal gas at the same temperature and pressure. This factor tends to increase with high pressure and lower temperature which means that it's inversely proportional to the absolute temperature of the gas and proportional to the pressure. This can also be explained with our common sense when in gas we have higher pressure the volume decreases and when we have higher temperature the volume increases therefore explaining the relationship between the compression factor. This factor reveals information in regard to the intermolecular interactions in real gases depending on the value of Z. • Z = 1 there is no attraction or repulsion between the molecules of the gas. • Z < 1the intermolecular attraction forces between the molecules dominant. • Z >1 the intermolecular repulsive forces between the molecules dominant which causes more volume to be occupied.
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