Heat Measurement Concepts

Units of Measurement

• Calorie

  • Definition: Energy to heat 1 gram of water by 1°C.
  • Appears on food packaging as Calorie (capital C), which is actually a kilocalorie (kcal).

• Joule (SI Unit)

  • Definition: 1 Joule = 1 kg·m²/s².
  • Most common unit used in scientific measurements.

Measuring Heat (q)

• Different methods to calculate heat:

Specific Heat Capacity

• Definition: Intensive property, independent of material amount.
• Symbol: Lowercase 'c' in textbook (also seen as lowercase 's').
• Formula:
  • ( q = m \times c \times \Delta T )
    • ( m ) = mass
    • ( c ) = specific heat capacity
    • ( \Delta T ) = change in temperature (( T_{final} - T_{initial} ))
• Units: Joules/gram°C

Unit Conversion

• Ensure mass is in compatible units (e.g., grams if specific heat is in joules/gram°C).
• Temperature can be in °C or Kelvin since it is a difference.

Heat Capacity

• Definition: Extensive property, dependent on object's mass.
• Symbol: Typically a capital 'C'.
• Formula:
  • ( q = C \times \Delta T )
    • ( C ) = heat capacity (Joules/°C)
    • ( \Delta T ) = change in temperature
• Used often in contexts like bomb calorimeters.

Next Topic

• Calorimeters
  • Detailed analysis of how calorimeters are used to measure heat.