Temperature and Thermal Energy

  • Difference Between Temperature and Thermal Energy

    • Temperature

    • Defined as the degree of hotness or coldness of an object.

    • Represents the average kinetic energy of particles in matter.

    • Molecules move faster with higher temperatures.

    • Thermal Energy

    • Total energy required to increase or decrease an object's temperature.

    • Example: To raise the temperature of a liquid from 20°C to 30°C, thermal energy must be added.

    • To lower the temperature, thermal energy must be removed.

  • Measuring Units

    • Ice temperature measured in degrees Celsius (°C).
    • Thermal energy measured in Joules (J):
    • All forms of energy are quantified in joules.

  • Thermometers

    • Instruments used to measure temperature; commonly filled with mercury.
    • Human body temperature is typically 37°C.
    • Mercury’s properties:
    • Regular expansion is ideal for thermometers.
    • When temperature increases, liquid height changes in a consistent manner (e.g., 0.5 cm for a 1°C increase).

  • States of Matter

    • Three states: solid, liquid, and gas.
    • Particle Arrangement
    • Solid: Particles are closely packed with narrow intermolecular spaces.
      • Movement is restricted to vibrational motion due to strong intermolecular forces.
    • Liquid: Particles are less closely packed than solids; can flow but still maintain a definite volume.
    • Gas: Particles are far apart with minimal intermolecular forces; can expand and fill the container.

  • Factors Affecting Thermal Energy

    • Mass:

    • Greater mass correlates with higher thermal energy.

    • If two beakers contain liquids, and one is larger (more mass), it requires more thermal energy to heat.

    • Temperature Change:

    • More energy is needed to increase temperature by larger increments (e.g., from 10°C to 30°C requires more thermal energy than a smaller increment).

    • An increase in the number of particles in a sample (e.g., 10 particles vs. 20 particles) also requires more energy.

  • Energy Transformation

    • Thermal energy can convert to kinetic energy, causing particle motion to increase.
    • This concept aligns with the laws of energy preservation.

  • Boiling vs. Warming

    • Boiling requires more thermal energy than warming, as boiling temperatures are typically higher than warming temperatures.