chemistry unit 5.4
Heating solids
When solids are heated they expand.
The particles in solids are arranged in a fixed pattern.
The particles are held together strongly and are tightly packed.
the particles in the solid vibrate .
The heat energy is transferred to the particles .
The more energy the particles have , the more ,they vibrate .
As the particles vibrate more , they take up more space.
When a solid is heated the particles vibrate more and take up more space.
melting solids
Melting is the process of a solid substance transitioning into a liquid state.
It occurs when heat is applied to a solid, causing its particles to gain kinetic energy.
As the particles vibrate more vigorously, they overcome the intermolecular forces holding them in a fixed structure.
The temperature at which melting occurs is called the melting point, which is characteristic of each substance.
During melting, the temperature remains constant until all of the solid has transformed into a liquid.
Examples of melting include ice melting into water at 0 degrees Celsius and candle wax melting when heated.
The opposite process, where a liquid turns into a solid, is called freezing or solidification.
Boiling liquids
Boiling is the process where a liquid substance changes into a gas state throughout the entire volume of the liquid.
It occurs when the temperature of the liquid reaches its boiling point, where its vapor pressure equals the pressure of the surrounding environment.
Heat energy is continuously added to the liquid, increasing the kinetic energy of its particles.
As the temperature rises, the vapor pressure of the liquid increases until it matches the external pressure, causing bubbles of vapor to form within the liquid.
When these bubbles rise to the surface of the liquid and escape into the surrounding atmosphere, the process is called boiling.
The boiling point is a characteristic property of each substance and depends on factors such as atmospheric pressure.
Examples of boiling include water boiling at 100 degrees Celsius at standard atmospheric pressure and the boiling of liquid nitrogen at its boiling point of -196 degrees Celsius.
The opposite process, where a gas changes into a liquid, is called condensation.
Cooling gases
Cooling gases involves reducing the temperature of a gas, causing its particles to lose kinetic energy.
Methods include refrigeration, expansion, or contact with a colder surface.
Temperature reduction leads to decreased particle speed, pressure, and volume.
Cooling can cause condensation if temperature drops below the gas's dew point.
Crucial for air conditioning, refrigeration, and gas liquefaction.
Different gases have different condensation points.
Control is essential for specific applications like food preservation or industrial processes.
Precision is crucial in scientific research and industrial applications.
Freezing liquids
Freezing is the transition of a liquid substance into a solid state.
It occurs when the temperature of the liquid reaches its freezing point.
As temperature decreases, the kinetic energy of liquid particles decreases.
Intermolecular forces between particles become strong enough to form a solid structure.
The freezing point is unique to each substance and can vary with pressure.
Temperature remains constant during freezing until all liquid converts to solid.
Examples include water freezing into ice at 0 degrees Celsius.
The opposite process is melting, where a solid turns into a liquid.