Specific Heat1

What is Specific Heat Capacity?

Abstract

Specific heat capacity is the amount of heat required to raise the temperature of a substance (let’s say 1 kg of mass) by 1 kelvin. The specific heat of a substance represented by symbol C can be formulated as:

C∆Q / m ∆T

The increase in temperature of the body is directly proportional to the amount of heat absorbed by the body. Plus, it is also directly proportional to the mass of the body or substance. Thus, we can say that ∆Q is directly proportional to m ∆T.

In the International System of Units, mass is measured in kilograms (kg), the temperature is taken in Kelvin (k), and heat in joules. Thus, the SI unit of specific heat capacity is joule per kelvin per kg Jkg-1K-1.

The specific heat capacity of substances is not constant but changes from state to state or depends on the type of material.

Definition

The specific heat of a substance is the quantity of heat required to raise the temperature of the 1-kilogram mass of the substance through 1Kelvin.

The specific heat capacity of the material is a physical attribute. Itis also an instance of a substantial property since its value is directly proportional to the magnitude of the system being analyzed.

Mathematical Form {Formula/equation}

Ordinarily, each time a body is heated, its temperature increases. An increase in the temperature of a body is found to be proportional to the amount of heat absorbed by it. It has also been observed that the quantity of heat ∆Q required to raise the temperature ∆T of a body is proportional to the mass m of the body. Thus the equation is,

ΔQ∝mΔT

Or

ΔQ=c mΔT

This ∆Q is the quantity of heat absorbed by the body and c is the constant of proportionality referred to as the specific heat capacity or simply specific heat.

Thus, the specific heat of a material formula is

c= ΔQ/mΔT

Explanation of equation

The dependence of specific heat upon temperature and mass is understandable. As the kinetic energy of an atom or molecule is proportional to temperature, so the internal energy is directly proportional to the total temperature and the range of molecules or atoms.

Further Reading:  Geiger Muller Counter [Principle, Working, & Uses]

Since the absorbed heat is equivalent to the shift in the internal energy, so heat is proportional to the mass and change of temperature of the body.

The transferred heat depends upon the substance in order, as an instance, the heat required to raise the temperature will be not the same for alcohol compared to water. For the same substance, the ∆Q also be contingent upon the phase (gas, liquid, or solid).

SI Units of Specific Heat Capacity

In SI units, mass is measured in kilograms (kg), heat ∆Q is measured in joule (J) and temperature increase ∆T is measured in kelvin (K). Thus, the SI unit of specific heat is joule per kelvin per kg (J/K/kg, J/ (kg K), Jkg-1K-1.

Significance of large Specific Heat Capacity of Water
  • The specific heat of water is 4200 Jkg-1K-1and of soil is all about 8 10 Jkg-1K-1. Because of this the temperature of soil would increase five times more than compared to the exact same mass of water at precisely the same amount of heat. Thus, the temperature of land rises and falls more rapidly than that of the sea.

Hence, the temperature variations from summer to winter are much smaller at places near the sea than land far away from the sea. For instance, as you can observe in Karachi.

  • The heat capacity of water contains a fantastic deal regarding controlling extremes in the environment. As an example, the fish from seas and ponds are joyful because the heat capacity of water at the pond usually means the temperature of this water tends to always be relatively the same from day to night time. They don’t really need to be worried about turning to the air conditioner or putting on warm clothes.
  • Water comes with a large specific heat capacity. It is very helpful in preserving and carrying thermal energy because of the high specific heat capacity.
  • The cooling system of automobiles utilized water to remove undesirable thermal energy. In a Vehicle, a large quantity of heat is produced by its own engine due to which temperature keeps on rising.

Specific Heat1

The engine will cease unless it is not cooled down. Water circulating across the engine keeps regulating temperature. Water absorbs the undesired thermal energy of this engine and dissipates heat through its radiator.

  • In the central heating system, hot water can also be used to transmit thermal energy through pipes from boilers to radiators. These radiators are mended at suitable places within houses.
Further Reading:  Theory of Relativity

Specific Heat2

 

Specific Heat Capacity of a few common substances

MCQs:

  • What is specific heat capacity?
    • A) The amount of heat required to freeze a substance
    • B) The amount of heat required to raise the temperature of a substance by 1 Kelvin
    • C) The amount of heat required to evaporate a substance
    • D) The amount of heat required to raise the temperature of a substance by 1 degree Celsius
    • Answer: B
  • What are the SI units of specific heat capacity?
    • A) Joules per kilogram per Kelvin (J/kg/K)
    • B) Kilograms per joule per Kelvin (kg/J/K)
    • C) Joules per kilogram per degree Celsius (J/kg/°C)
    • D) Joules per kelvin per kilogram (J/K/kg)
    • Answer: A
  • Which of the following is NOT a factor affecting the specific heat capacity of a substance?
    • A) Temperature
    • B) Mass
    • C) Phase (solid, liquid, gas)
    • D) Color
    • Answer: D
  • The specific heat capacity of water is approximately:
    • A) 100 J/kg/K
    • B) 4200 J/kg/K
    • C) 2000 J/kg/K
    • D) 5000 J/kg/K
    • Answer: B
  • Why does water have a significant effect on moderating temperature changes in coastal areas?
    • A) Because water has a low specific heat capacity
    • B) Because water has a high specific heat capacity
    • C) Because water evaporates quickly
    • D) Because water absorbs heat slowly
    • Answer: B
  • What is the mathematical form of specific heat capacity?
    • A) c = ∆Q * ∆T / m
    • B) c = ∆Q / ∆T * m
    • C) c = ∆T / ∆Q * m
    • D) c = ∆T * m / ∆Q
    • Answer: A
  • The quantity of heat required to raise the temperature of a substance is directly proportional to:
    • A) The temperature change
    • B) The mass of the substance
    • C) The specific heat capacity
    • D) The color of the substance
    • Answer: B
  • What does the symbol ‘∆’ represent in the formula for specific heat capacity?
    • A) Heat capacity
    • B) Mass
    • C) Change
    • D) Temperature
    • Answer: C
  • Why does water have a larger specific heat capacity compared to soil?
    • A) Because water is denser than soil
    • B) Because water is a better conductor of heat than soil
    • C) Because water molecules have stronger intermolecular forces than soil particles
    • D) Because water molecules have weaker intermolecular forces than soil particles
    • Answer: C
  • What is the SI unit for specific heat capacity?
    • A) J/kg
    • B) J/°C
    • C) J/m^3
    • D) J/kg/K
    • Answer: D
  • How does the specific heat capacity of a substance vary with temperature?
    • A) It remains constant
    • B) It increases linearly
    • C) It decreases linearly
    • D) It varies depending on the substance
    • Answer: D
  • Which of the following materials would have the highest specific heat capacity?
    • A) Iron
    • B) Wood
    • C) Water
    • D) Air
    • Answer: C
  • What property does specific heat capacity represent?
    • A) The ability of a substance to conduct electricity
    • B) The ability of a substance to conduct heat
    • C) The ability of a substance to change color
    • D) The ability of a substance to resist temperature change
    • Answer: D
  • How is specific heat capacity defined?
    • A) The amount of heat required to change the phase of a substance
    • B) The amount of heat required to evaporate a substance
    • C) The amount of heat required to raise the temperature of a substance by 1 Kelvin
    • D) The amount of heat required to cool a substance to absolute zero
    • Answer: C
  • What is the significance of specific heat capacity in the cooling system of automobiles?
    • A) It helps to increase the engine temperature
    • B) It helps to decrease the engine temperature
    • C) It has no effect on the engine temperature
    • D) It helps to improve fuel efficiency
    • Answer: B
Further Reading:  Blackbody and Blackbody Radiation

 

Summary

In conclusion, specific heat capacity plays a crucial role in understanding how substances respond to changes in temperature. Defined as the amount of heat required to raise the temperature of a substance by 1 Kelvin per unit mass, specific heat capacity is represented by the formula . This property is fundamental in various applications, from designing cooling systems in automobiles to regulating temperatures in central heating systems.

The SI unit for specific heat capacity is joules per kelvin per kilogram (J/kg/K), emphasizing its importance in energy calculations. Moreover, substances exhibit different specific heat capacities depending on their composition and phase. Water, with its high specific heat capacity of 4200 J/kg/K, is particularly significant in moderating temperature changes in coastal areas and maintaining stable environmental conditions for aquatic life.

Understanding specific heat capacity enables engineers and scientists to design efficient heating and cooling systems and to predict how substances will respond to changes in their surroundings.