Hello,world 1-"the intermolecular attractive forces between gas particles are very weak due to the large intermolecular distances separating them" Is that true? this is wriiten in my textbook and it is confusing me because i've always thought of it in a different way ,I thought the intermolecular attractive forces between gas molecules are very weak because they move in a very very large speed so they don't have enough time to attract each other, But I feel some contradiction between the way i think and my textbook so I want to know which of these two concepts are true or both of them are true? 2-I've read before that an ideal gas doesnot exist ,so what is the importance of imaging such an ideal gas if it doesnot exist?Is it because many gases have very similar properties to the properties of that ideal guy in high temperatures and low pressures?I can't really imagine what is an ideal gas although I've read many times about it..Does an ideal gas remains ideal at high pressure and low temperature? 3-what is the relation between the general gas laws(Charle,Boyle,Jolly) and the kinetic molecular theory of gases?The ideal gas follows both of them...let me rephrase this question, why should the gas have the following properties : A gas consists of a collection of small particles traveling in straight-line motion and obeying Newton's Laws. The molecules in a gas occupy no volume (that is, they are points). Collisions between molecules are perfectly elastic (that is, no energy is gained or lost during the collision). There are no attractive or repulsive forces between the molecules. The average kinetic energy of a molecule is 3kT/2. (T is the absolute temperature and k is the Boltzmann constant.) in order to follow exactely the general laws of gases?what is the relation between having this properties and following exactely the general gas laws?I hope you could understand my problem here.. 4-why does A mole of any gas at STP occupy the same volume?the answer to this question in my textbook is that 1- the no. of particles of one mole of any gas is constant 2.the intermolecular spaces of all gases is constant at STP. That's not very bad but what about the size of the molecules?the sizes of molecules are different for different gases indeed SO,why does A mole of any gas at STP occupy the same volume? 5-"At the same pressure and temperature,the intermolecular spaces between the molecules of the ideal gases are constant?because the intermolecular attractive forces between the molecules of the ideal gas is negligible,so the intermolecular spaces doesnot depend upon the mass of of the molecule or the type of the gas". That's stupid!what does that mean??what is the relation between the mass of the molecule and the intermolecular distances betweern molecules? 6-the frequency of the molecule is calculated from the relation : frequency = V/2L how was this equation derived?I don't understand it 7-what is the rest energy? Thanks in advance.