CHEM 170 1st Edition Lecture 1Outline of Current Lecture I. Kinetic Theory of GasesII. Root Mean Squared Speed(Urms)III. Graham’s Law of EffusionCurrent LectureChapter 11 – GasesGases are a phase of matter. Gases have a low density; in other words, gases consist of small particles separated by large distances. Gases fill a container and its small particles are in constant motion.Kinetic Theory of Gases:1 gases have small particles separated by large distances2 these small particles are in constant motion3 these particles act like hard spheres (there is no attractive or repulsive interactions)4 the average kinetic energy (KE) is dependent on temperature (T); Ek∝TRoot Mean Squared Speed (Urms)Given:KE=12mu2KE=32RT*R=gas constant=8.314Jmol × Ku2=u+u22+…+uN2N*N=avagadro’ snumber=6.02 ×1023NAEk=32RTNA(mu2)=32RTM12u2=32RT*M=molar mass=NA×mu2=3 RTMurms=√u2=√3 RTMThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Grahams Law of Effusion:The speed at which gas particles move is inversely related to their mass.In other words, if there are two gas particles of different masses with the same kinetic energy, then the particle with the smaller mass will move faster than the particle with a larger mass. This can be understood by looking at the equationKE=12mu2 → u=√(KE)2m and the equationurms=√u2=√3 RTM where velocity is inversely related to mass.To compare the speed of two gases we can use the equation for Urms. urms=√u2=√3 RTMIf the temperature was held constant and there was gas A and gas B, thenurms(A)urms(B)=√3 RTMA√3 RTMBsince (3 RT ) is a
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