Kmt Flashcards
What’s the kinetic molecular theory
The Kinetic Molecular Theory (KMT) is a scientific model that explains the behavior of matter in terms of the motion of its particles (atoms, molecules, or ions). It provides a framework to understand how matter exists in different states (solid, liquid, gas) and how it changes from one state to another.
Particles are in constant motion
The particles (atoms, molecules, ions) of matter are always moving, and their motion is related to the temperature of the substance
Collisions are elastic
Collisions are elastic: When particles collide with each other or with the walls of their container, the collisions do not result in any loss of kinetic energy. Instead, the energy is transferred between the particles.
Particles are far apart in gases
In gases, particles are much farther apart compared to solids or liquids, allowing them to move freely and occupy the full volume of their container.
Particles in liquids and solids are closer together
Therefore they interact more strongly with each other
Particles in solids, liquids and gases
In solids, the particles are tightly packed and only vibrate in place.
In liquids, the particles are still close together but can move past each other, allowing liquids to flow and take the shape of their container while maintaining a fixed volume.
In gases, the particles are far apart and move freely in all directions. They spread out to fill the entire volume of their container
Motion and intermolecular forces
The motion is minimal due to the strong intermolecular forces between particles. This limited motion and the strong forces keep solids in a fixed shape and volume.
The intermolecular forces are weaker than in solids, but still significant enough to hold the liquid together.
The intermolecular forces are very weak, allowing the gas particles to move independently of each other.
Melting (solid to liquid)
Melting (Solid to Liquid): When a solid is heated, the kinetic energy of its particles increases. As the particles vibrate more, the forces holding them together weaken, and they begin to move past each other. This transition from solid to liquid occurs when the temperature reaches the substance’s melting point.
Freezing (liquid to solid)
When a liquid is cooled, the kinetic energy of its particles decreases, and the particles move slower. As the temperature drops, the attractive forces between the particles become stronger, causing the liquid to solidify
vaporization
Vaporization (Liquid to Gas): When a liquid is heated, the particles gain kinetic energy and begin to move faster. If enough energy is provided, some particles will break free from the liquid’s surface and enter the gas phase. This occurs at the boiling point, but evaporation can also occur at lower temperatures
Condensation (gas to liquid)
When a gas is cooled, the kinetic energy of the particles decreases, causing them to move slower. As the particles slow down, attractive forces between them become more significant, causing the gas to condense into a liquid
Sublimation (solid to gas)
In some substances, like dry ice (solid CO₂), heating causes the particles to transition directly from the solid phase to the gas phase without becoming a liquid. This occurs when the kinetic energy of the particles
becomes high enough to overcome the forces holding them in the solid state.
It happens at temperatures and pressures below the substance’s melting and boiling point.
Eg dry ice(solid co2) sublimates at room temperature, changing directly from Co2 to carbon dioxide gas
Deposition
The reverse of sublimation, where a gas directly transitions into a solid without becoming a liquid. This occurs when the kinetic energy of the particles decreases enough for them to come together and form a solid structure.
Temperature
Temperature is directly related to the average kinetic energy of the particles in a substance. As temperature increases, the particles move faster (higher kinetic energy), and as temperature decreases, the particles move slower (lower kinetic energy). This change in
kinetic energy is responsible for the different phases of matter and the transitions between them.
Room temperature
Room temperature is typically considered to be around 20°C to 22°C (68°F to 72°F). This is the temperature range that most people find comfortable in a living or working environment
