Solids A solid is matter that has a definite shape and a definite volume. The attractive forces between the particles in a solid are strong and pull them close together.
Solids (cont.) Describe the movement of particles in a solid and the forces between them.
Liquids A liquid is matter with a definite volume but no definite shape. Liquids flow and can take the shape of their containers.
Liquids (cont.) The particle motion in a liquid is faster than the particle motion in a solid.
Gases A gas is matter that has no definite volume and no definite shape. Compared to the particles in the solid and the liquid states, the particles in gases are far apart.
Gases (cont.) In a gas, the forces of attraction between the particles are not strong enough to keep the particles close together. Because the particles in gas are moving quickly, the distance between particles increases, and the attractive forces between particles decreases. The gas state of a substance that is normally a solid or a liquid at room temperature is called vapor.
In some matter, particles can only vibrate in place. The particles are close together, and there are strong forces among them.
In other matter, the particles are far enough apart that particles can flow past other particles. The forces among these particles are weaker than those shown above.
In another group of matter, the particles are far apart and there is little or no attraction among the particles.
Which describes matter with a definite volume but no definite shape? A. solid B. plasma C. liquid D. gas
Compared to a liquid, which best describes the particles of a gas? A. closer together B. farther apart C. slower moving D. tightly packed
Kinetic and Potential Energy (cont.) Temperature is a measure of the average kinetic energy of all the particles in an object. Temperature can be thought of as the measure of how much the particles in a object/substance are moving. Within a given substance, a temperature increase means that the particles, on average, are moving at greater speeds.
Kinetic and Potential Energy (cont.) How is temperature related to particle motion?
Thermal Energy Thermal energy is the total potential and kinetic energy of an object. You can change an object s state of matter by adding or removing thermal energy. If enough thermal energy is added or removed from an object, a change of state can occur.
Thermal Energy (cont.) How do thermal energy and temperature differ?
Solid to Liquid or Liquid to Solid To change matter from a solid to a liquid, thermal energy must be added. Once a solid reaches the melting point, additional thermal energy is used by the particles to overcome their attractive forces, the particles move farther apart and potential energy increases.
Adding thermal energy to matter causes the particles that make up the matter to increase in kinetic energy, potential energy, or both.
Solid to Liquid or Liquid to Solid (cont.) Freezing is a process that is the opposite of melting. The temperature at which matter changes from the liquid state to the solid state is its freezing point.
At the boiling point, the potential energy of particles begins increasing.
Liquid to Gas or Gas to Liquid (cont.) When a gas loses enough thermal energy, the gas changes to a liquid, or condenses. The change of state from a gas to a liquid is called condensation.
States of Water Water is the only substance that exists naturally as a solid, a liquid, and a gas on Earth. At 0 C, water molecules vibrate so rapidly that they begin to move out of their places, the particles overcome their attractive forces, and melting occurs.
States of Water (cont.) When water reaches 100 C, the boiling point, liquid water begins to change to water vapor. Cooling water vapor changes the gas to a liquid, and cooling the water further changes it to ice.
States of Water (cont.)
States of Water (cont.) Describe the changes in thermal energy as water goes from a solid to a liquid.
Conservation of Mass and Energy When matter changes state, matter and energy are always conserved.
Which term refers to the average kinetic energy of all the particles in an object? A. thermal energy B. temperature C. sublimation D. evaporation
Which substance exists naturally on Earth as a solid, liquid and gas? A. carbon B. carbon dioxide C. salt D. water