Specific Heat of Some Common Substances

The specific heat capacities of some common substances at standard temperature and pressure (STP), typically expressed in joules per gram per degree Celsius (J/g°C) or kilojoules per kilogram per degree Celsius (kJ/kg°C):

1. Water:

   • Specific heat capacity: $4.18\text{J/g°C}$ or $4.18\text{kJ/kg°C}$ Water has one of the highest specific heat capacities of common substances, making it effective at storing and transferring heat. This property contributes to water's ability to moderate temperature changes in the environment and plays a crucial role in climate regulation and thermal comfort.

2. Aluminum:

   • Specific heat capacity: $0.90\text{J/g°C}$ or $0.90\text{kJ/kg°C}$ Aluminum has a relatively low specific heat capacity compared to water, meaning it requires less energy to raise its temperature by one degree Celsius. This property makes aluminum useful in applications where heat transfer efficiency is important, such as in cooking utensils and heat exchangers.

3. Copper:

   • Specific heat capacity: $0.39\text{J/g°C}$ or $0.39\text{kJ/kg°C}$ Copper has a lower specific heat capacity compared to water and aluminum, making it even more efficient at transferring heat. This property makes copper widely used in electrical wiring, plumbing, and heat sinks in electronic devices.

4. Iron:

   • Specific heat capacity: $0.45\text{J/g°C}$ or $0.45\text{kJ/kg°C}$ Iron has a specific heat capacity similar to copper but slightly higher. It is commonly used in construction materials, machinery, and cookware due to its strength, durability, and thermal conductivity.

5. Air (at constant pressure):

   • Specific heat capacity: $1.01\text{J/g°C}$ or $1.01\text{kJ/kg°C}$ The specific heat capacity of air depends on its composition and conditions. At constant pressure and STP, dry air has a specific heat capacity of approximately $1.01\text{J/g°C}$ or $1.01\text{kJ/kg°C}$. This property influences the temperature regulation of Earth's atmosphere and is important in HVAC systems and thermal comfort considerations.

These values may vary slightly depending on factors such as temperature, pressure, and impurities in the substances. Understanding the specific heat capacities of common substances is essential in various fields, including thermodynamics, engineering, materials science, and environmental science.