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.