General Knowledge - Chemistry - Discussion

Heat capacity (usually denoted by a capital C, often with subscripts), or thermal capacity, is the measurable physical quantity that shows the amount of heat required to change the temperature of an object or body by a given amount. In the International System of Units (SI), heat capacity is expressed in units of joule(s) (J) per kelvin (K). This quantity varies with the size (amount) of the body.

Derived quantities that specify heat capacity as an intensive property, i.e., independent of the size of the body or amount of a sample, are the molar heat capacity, which is the heat capacity per mole of a pure substance, and the specific heat capacity, often simply called specific heat, which is the heat capacity per unit mass of a material. Occasionally, in engineering contexts, a volumetric heat capacity is used. Because heat capacities of materials tend to mirror the number of atoms or particles they contain, when intensive heat capacities of various substances are expressed directly or indirectly per particle number, they tend to vary within a much more narrow range.

Temperature reflects the average kinetic energy of particles in matter while heat is the transfer of thermal energy from high to low temperature regions. Thermal energy transmitted by heat is stored as kinetic energy of atoms as they move, and in molecules as they rotate. Additionally, some thermal energy may be stored as the potential energy associated with higher-energy modes of vibration, whenever they occur in interatomic bonds in any substance. Translation, rotation, and a combination of the two types of energy in vibration (kinetic and potential) of atoms represent the degrees of freedom of motion which classically contribute to the heat capacity of atomic matter (loosely bound electrons occasionally also participate). On a microscopic scale, each system particle absorbs thermal energy among the few degrees of freedom available to it, and at high enough temperatures, this process contributes to a specific heat capacity that classically approaches a value per mole of particles that is set by the Dulong-Petit law. This limit, which is about 25 joules per kelvin for each mole of atoms, is achieved by many solid substances at room temperature (see table below).

For quantum mechanical reasons, at any given temperature, some of these degrees of freedom may be unavailable, or only partially available, to store thermal energy. In such cases, the specific heat capacity will be a fraction of the maximum. As the temperature approaches absolute zero, the specific heat capacity of a system also approaches zero, due to loss of available degrees of freedom. Quantum theory can be used to quantitatively predict specific heat capacities in simple systems.

Lets understand the Sp. heat: Amount of heat required to raise the body temp. by 1'C.

-->> lets take two different bodies & start heating assuming (initially both the bodies are at same temp, both the bodies needs different amount of energy to raise their temp. by 1'C ), that means the body whichever needs more energy to raise its temp by 1'C has more Sp. Heat.

Lets understand the thermal conductivity:

Lets take two bodies of same shape & size of two different materials and start heating at one end, after a minute observe the temperatures at another end, you feel both the bodies are having different temperatures,

It means the body which has more temp. has high thermal conductivity.

The relation between Sp. heat & Thermal conductivity is given by the term thermal diffusivity,

Observe carefully the terms in thermal diffusivity, & reduce one term by keeping another term constant, & observe the changes you will understand the difference between Sp. Heat & Thermal conductivity.

Thermal capacity also referred as heat capacity it is the amount of heat required to change the temperature of an object by a certain degree.

On the other hand, specific heat capacity also referred to as the specific heat of a material, is the amount of heat needed to raise the temperature of an object per unit mass of that object.

The heat capacity is the amount of heat required to raise the temperature of an object or substance one degree.

The thermal capacity is the amount of heat required to raise the temperature of an object or substance one kelvin.

Heat - 1 degree.

Thermal - 1 kelvin.

The Heat capacity is the amount of heat required to raise the temperature of an object by 1°C.

The specific heat of a substance is the amount of energy required to raise the temperature of 1 gram of the substance by 1°C.

So, the given answer is Right.

Heat capacity (usually denoted by a capital C, often with subscripts) , or thermal capacity, is the measurable physical quantity that characterizes the amount of heat required to change a substance's temperature by a given amount.

The heat required to raise the temperature of a body by 1 K is called thermal capacity. In other words, when q is the heat supplied to the body and the temperature raises by 1 K, then the thermal capacity of body is q.

The thermal capacity of a body is defined as the amount of heat required to raise temperature of the body by 1 kelvin.

Mathematically, C=ms.
Where, m=mass of the body.
s=specific heat capacity.

Thermal Capacity

The quantity of heat necessary to produce a unit change of temperature in a unit mass of a substance. In SI, the unit is to the joule per kilogram kelvin (J/kg-K).

Definition: The quantity of heat necessary to produce a unit change of temperature in a unit mass of a substance. In SI, the unit is to the joule per kilogram kelvin (J/kg-K).