Thermal Energy Transfer: Matter and Heat - PDF
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Uploaded by CreativeSunstone4036
Al Rawabi Middle & High School
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Summary
This document covers concepts related to thermal energy transfer, including the particulate nature of matter, specific heat capacity, latent heat, conduction, convection, and radiation. The content includes formulas and explanations of how heat transfers occur. This is a physics document and contains many topics related to heat.
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Particulate Nature of Matter Three states of matter are solids, liquids, and gases. Each state is characterized by different properties. A substance's state of matter is determined by the separation between molecules, intermolecular force, and the available kinetic energy. Soli...
Particulate Nature of Matter Three states of matter are solids, liquids, and gases. Each state is characterized by different properties. A substance's state of matter is determined by the separation between molecules, intermolecular force, and the available kinetic energy. Solids feature closely packed particles and the strongest intermolecular force. Gases feature the weakest intermolecular force. Matter can transition between states. During a state change, temperature remains constant as energy is used for the transformation. Internal energy is the sum of all potential and kinetic energy of all the particles in a substance. Thermal Energy Transfers (Specific Heat Capacity) Different materials have different heat capacities. Specific heat capacity is used to compare heat capacities. The specific heat capacity of a substance is the energy transfer required to raise 1 kg by one degree. Specific Heat Capacity Formula c = Q / mΔT m = Mass of the substance c = Specific heat capacity of the substance ΔT = Difference in temperature (final temperature minus initial temperature) Specific heat capacity is measured in J/kg⋅K (Joules per kilogram-kelvin). Thermal Energy Transfers (Specific Latent Heat of Fusion) Specific latent heat of fusion is the amount of energy transferred when 1 kg of a substance changes from one phase to another. Latent Heat of Fusion Formula L=Q/m L = specific latent heat of fusion Q = energy transferred m = mass of the substance Latent heat is measured in J/kg Activities Example Crushed ice at -10°C is heated in a container, and temperature is recorded over time. The flat section AB on a time-temperature graph indicates a change of state, ice to water. The heat supplied is used to change ice from a solid to liquid state, bonds between molecules are broken during the phase change. Fusion applies to phase changes between solid to liquid and liquid to solid. Thermal Energy Transfers (Specific Latent Heat of Vaporization) Specific latent heat of vaporization is the amount of energy transferred when 1 kg of a substance changes from one phase to another. Latent Heat of Vaporization Formula L=Q/m L is the specific latent heat of vaporization. Q is the energy transferred. m is the mass of the substance. Thermal Energy Transfer Thermal energy transfers from hot to cooler areas through: ○ Conduction ○ Convection ○ Radiation Conduction Energy transfer mainly takes place without the actual movement of atoms during conduction Conduction occurs through two mechanisms: ○ Atomic vibrations ○ Free electron collisions Metals are good conductors due to the high number of de-localized electrons. Convection Energy transfer takes place with the actual movement of atoms due to variation in density. Convection explains land and sea breezes. Winds are driven by the uneven heating of the Earth's surface. Radiation Only method of thermal energy transfer that doesn't require matter. Involves the transfer of heat by means of electromagnetic radiation, generally in the infrared region.
