LAMIA RAO XI KINETIC MOLECULAR THEORY

MondayTuesdayWednesdayThursdayFriday Introduction to Kinetic molecular theory by showing examples Explanation of KMT by lecture and by allowing groups of students to do an experiment and share their observations and inference Showing video of KMT and asking questions to share their views Relating KMT with gases, liquids and solids Quiz for assessment

KINETIC MOLECULAR THEORY OF GASES  Introduction  Assumptions  Explanation  Experiment

The kinetic theory of gases describes a gas as a large number of small particles (atoms or molecules), all of which are in constant, random motion. The rapidly moving particles constantly collide with each other and with the walls of the container. Kinetic theory explains macroscopic properties of gases, such as pressure, temperature, or volume, by considering their molecular composition and motion. The pressure is due to collisions between molecules moving at different velocities and walls of container.atomsmolecules randommotionmacroscopiccollisions While the particles making up a gas are too small to be visible, the jittering motion of pollen grains or dust particles which can be seen under a microscope, known as Brownian motion, results directly from collisions between the particle and gas molecules. As pointed out by Albert Einstein in 1905, this experimental evidence for kinetic theory is generally seen as having confirmed the existence of atoms and molecules.Brownian motion Albert Einstein

1. The gas consists of very small particles, all with non-zero mass.mass 2. The number of molecules is so large that statistical treatment can be applied. 3. These molecules are in constant, random motion. The rapidly moving particles constantly collide with the walls of the container.random 4. The collisions of gas particles with the walls of the container holding them are perfectly elastic. 5. Except during collisions, the interactions among molecules are negligible (they exert no forces on one another).interactionsnegligibleforces 6. The total volume of the individual gas molecules added up is negligible compared to the volume of the container. This is equivalent to stating that the average distance separating the gas particles is large compared to their size.volumesize 7. The molecules are perfectly spherical in shape, and elastic in nature. 8. The average kinetic energy of the gas particles depends only on the temperature of the system.kinetic energy temperature

Students will be asked to form small groups and a glass container with marbles will be given and one student will be asked to shake it continuously and another student will be given a rubber ball and asked to bounce it once and then note its progress. Considering the marbles as gaseous particles, the students will be asked to relate it with the assumptions 3,4,5 of KMT The collisions that occur in this container are very different from those that occur when a rubber ball is dropped on the floor. Collisions between the rubber ball and the floor are inelastic. A portion of the energy of the ball is lost each time it hits the floor, until it eventually rolls to a stop. In this container, the collisions are perfectly elastic.

Random motion of gaseous molecules Increasing pressure decreases the volume of gas at constant temperature Total pressure is the sum of partial pressures when volume and temperature are kept constant

Three states of matter and the comparative packing of their particles

Q.1. State true or false: i) Gas particles are packed tightly together. ___ ii) High temperature lowers down the average kinetic energy of the particles.___ iii) Increasing pressure at constant temperature will allow gas particles to move further apart.__ Q.2. Choose the correct answer: i) Gas molecules are in constant ___ motion a) Linear b) random c) translational d) directional ii) The collisions between gaseous molecules and the walls of container are ____ a) Inelastic b) elastic c) few d) none of the given answers Q.3. Devise an experiment to relate temperature and volume relationship between gaseous molecules. ____________________________________________________ _____________________________________________________________________ _____________________________________________________________________

Certificate of excellence

REFERENCES:   4/kinetic4.html 4/kinetic4.html  Video link: theory of gases  Test yourself link: theoryhttp://