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Key Definitions:

• Heat (Q): The transfer of thermal energy between substances due to a temperature difference.
  • Measured in joules (J).
  • Heat flows from hot to cold.
• Temperature (T): A measure of the average kinetic energy of the particles in a substance.
  • Measured in degrees Celsius (°C) or Kelvin (K).
• Internal Energy (U): The total energy stored in a substance due to both the kinetic energy of its particles (from their motion) and their potential energy (from intermolecular forces).
• Thermal Energy: The portion of internal energy associated specifically with the temperature (i.e., particle kinetic energy). </aside>

temperature scales:

• Celsius (°C): Based on the freezing (0°C) and boiling (100°C) points of water.
• Kelvin (K): Absolute temperature scale starting at absolute zero (0 K = -273.15°C).
• Conversion: T(K) = T(°C) + 273.15
• Absolute Zero: The temperature at which particles theoretically have zero kinetic energy (0 K).

methods of heat transfer:

1. Conduction
   • Occurs through direct contact between particles in solids.
   • Hotter particles vibrate more and pass on energy to cooler ones.
   • Example: A metal rod with one end in a flame.
2. Convection
   • Occurs in fluids (liquids and gases).
   • Heated fluid becomes less dense and rises; cooler fluid sinks.
   • Example: Warm air rising in a heated room.
3. Radiation
   • Transfer of heat by electromagnetic waves (infrared).
   • No medium required.
   • Example: Sunlight warming your skin.

specific heat capacity:

• The energy needed to raise the temperature of 1 kg of a substance by 1°C (or 1 K).
• Formula: Q = mcΔT
  • Q = heat energy (J)
  • m = mass (kg)
  • c = specific heat capacity (J/kg°C)
  • ΔT = temperature change (°C or K)
• High c → heats up slowly (e.g., water)
• Low c → heats up quickly (e.g., metal)

specific latent heat: