Kinetic Molecular Theory

What do we assume about the behavior of an ideal gas?   Gas molecules are in constant, random motion and when they collide they do not lose energy. Pressure is caused by the collision of gas molecules with their surroundings   The average kinetic energy of gas molecules is proportional to their temperature in Kelvins   Gas molecules are so small compared to the distance between them, they can be considered as having no volume   Gas molecules do not exert attractive of repulsive forces on each other

Are these true for a real gas? Gas molecules are in constant, random motion and when they collide they do not lose energy. Pressure is caused by the collision of gas molecules with their surroundings -Yes: we know molecules move (smells from the kitchen can be detected upstairs), and pressure is observed in all gas situations

  The average kinetic energy of gas molecules is proportional to their temperature in Kelvins   Yes: experimentally determined

  Gas molecules are so small compared to the distance between them, they can be considered as having no volume - No: when molecules are compressed or cooled, their volumes can become significant - For example: volumes of liquids and solids

  Gas molecules do not exert attractive of repulsive forces on each other -No: again, if compressed or cooled, molecules will absolutely attract or repel… how do we know?

Significance of KMT  Helps us predict gas behavior under most conditions of temperature and pressure  Most substances that are gases at 1atm clearly follow all gas laws as given in the ideal gas equation

When do ideal gases behave as real gases?