Specific heat capacity (or specific heat) is a simple thermodynamic measure that describes how much heat it takes to change the temperature of a single unit mass of an object by one degree Celsius (or Kelvin). It is used in the analysis of thermal, heat transfer, and energy use across many industrial applications, such as the design of heat exchangers, engines, and choice of materials for specific temperature ranges. Alfa Chemistry provides the following table summarizing the heat capacity of the most common materials you may encounter in life.
| Materials | Specific Heat Capacity (J/kg K) |
| Water | 4200 |
| Air | 1006 |
| Ice | 2040 |
| Glass | 840 |
| Boron carbide | 1000 |
| Graphite | 720 |
| Carbon fiber | 800 |
| Polyethylene | 1550 |
| Polypropylene | 1700 |
| Carbon dioxide | 840 |
| Brick | 800 |
| Porcelain | 1050 |
| Tungsten carbide | 292 |
| Diamond | 509 |
| PET | 1250 |
| Polycarbonate | 1200 |
| Carbon monoxide | 1040 |
| Sand | 830 |
| Limestone | 840 |
| Elektron 21 | 900 |
| Duralumin | 900 |
| Zirconium-tin alloy | 285 |
| Austenitic stainless steel | 500 |
| Mild steel | 510 |
| Gray iron | 460 |
| TZM alloy | 305 |
| Inconel | 460 |
| ETP | 380 |
| Cupronickel | 400 |
| Zamak 3 | 420 |
| Ruby | 750 |
| Uranium dioxide | 235 |
| Polystyrene | 1100 |
| Polyvinyl chloride | 880 |
| Nitrous oxide | 880 |
| Concrete | 1050 |
| Granite | 790 |
| Pure titanium | 520 |
| 6061 alloy | 896 |
| Zirconium-niobium alloy | 285 |
| Martensitic stainless steel | 460 |
| High-carbon steel | 490 |
| White iron | 540 |
| Mo-25 Re alloy | 220 |
| Hastelloy | 420 |
| Brass | 380 |
| Aluminium bronze | 380 |
| Soft tin solder | 167 |
| Salt | 880 |
| Kevlar | 1420 |
| Polyamide-Nylon | 1500 |
| Rubber | 1300 |
| Methan | 2200 |
| Stone wool | 700 |
| Quartz | 741 |
| Ti-6Al-4V | 560 |
| 7068 alloy | 1050 |
| Chromoly steel | 477 |
| Duplex stainless steel | 460 |
| Tool steel | 465 |
| Ductile iron | 460 |
| Tungsten-rhenium alloy | 140 |
| Stellite | 423 |
| Bronze | 435 |
| Beryllium copper | 420 |
| Amalgam | 210 |
| Sugar | 1244 |
| Wax | 2200 |
| Coal | 1380 |
| Asphalt concrete | 900 |
| Propane | 1630 |
| Glass wool | 840 |
| Aerogel | 1900 |
| Rose gold | 230 |
| Yellow gold | 200 |
| White gold | 220 |
| PH stainless steel | 460 |
| High-speed steel | 470 |
| Malleable iron | 465 |
| Pure tungsten | 130 |
| Invar | 505 |
| Constantan | 390 |
| Nickel silver | 377 |
| Galistan | 296 |
| Oak wood | 2000 |
| Pine wood | 2300 |
| Gasoline | 2200 |
| Diesel fuel | 2100 |
| Acetylene | 1674 |
What is Specific Heat Capacity?
Specific heat capacity is defined mathematically as the ratio of the amount of heat energy added to or removed from a system to the resulting change in temperature, expressed as:
Where:
- c is the specific heat capacity (J/kg·K),
- Q is the heat added or removed (Joules),
- m is the mass of the substance (kg),
- ΔT is the change in temperature (K or ℃).
It is important to note that specific heat capacities can vary depending on the conditions under which they are measured, including temperature, pressure, and phase of the material. The standard units for specific heat capacity in the SI system are joules per kilogram per kelvin (J/kg·K).
In thermodynamics, two forms of specific heat capacities are commonly encountered: cp and cv, which correspond to the specific heat at constant pressure and constant volume, respectively.
- Specific Heat at Constant Pressure (c_p): This value is typically higher than cv, because, at constant pressure, the substance does not undergo compression, allowing for more heat to be absorbed without increasing pressure.
- Specific Heat at Constant Volume (c_v): This is the heat capacity when the substance is kept at a constant volume. It is more commonly used in thermodynamic calculations for gases under controlled conditions.
These values are essential in understanding the behavior of materials under varying thermodynamic conditions and are a key parameter in material selection for industrial processes.
What are the factors that affect the specific heat capacity of a material?
A. Temperature: The specific heat of many materials changes with temperature, particularly in non-linear systems. For instance, gases generally have specific heat capacities that vary significantly with temperature due to changes in molecular kinetic energy.
B. Phase Change: Materials undergoing phase changes, such as from solid to liquid or liquid to gas, exhibit different specific heat capacities in each phase. For example, water has a significantly higher specific heat capacity in the liquid phase compared to its solid (ice) phase.
C. Material Composition and Structure: Materials with more complex molecular structures or those with significant intermolecular forces tend to have higher specific heat capacities. For example, hydrogen has a very high specific heat capacity compared to metals, owing to its simpler atomic structure and low mass.
What are the applications of specific heat capacity in industry?
In industrial applications, knowledge of the specific heat capacity of materials is vital for designing systems that manage heat transfer and energy efficiency. Some notable applications include:
- Thermal Insulation
- Heat Exchangers
- Energy Storage
- Materials Engineering
