Energy can be defined as a property which transformed or produced from work. In various natural phenomena, energies are different forms, such as kinetic, potential, mechanical, internal, chemical, nuclear power, electromagnetic spectrum, surface energy, etc. Energy conservation in thermodynamics says that energy can neither be created nor be destroyed but it may transfer one form to another. Heat or specific heat also another form of energies that yields or produces work. But heat is different from other sources like chemical, mechanical or electrical sources because all the other forms of energy completely change into work but thermal energy can not be wholly converted.
Another aspect of heat which required in learning chemistry when two objects with different temperatures come together, heat transit or flows from lower temperatures to higher temperatures.
Kinetic energies form of energy-producing by the motion of objects or particles. It works done on an object or particles, the object speeds up by gaining kinetic motion.
The potential energy formula first introduced by the 19th-century Scottish engineer and physicist William Rankine and define the energy held by an object because of its position relative to other objects. For examples of potential energy, displacing spring from its equilibrium position, lifting of the weight, turning of the blades in the wheel, etc.
Examples of Work and Energy
The usual convention in thermodynamics, work obtained from the system during the change regarded as positive where work done on the system by an outside agency negative. For the more precise concept of work and energy, we recall some relevant examples like oxidation or burning of coal or natural gas produces heat which ultimately enables the engine working. The mechanical work spent in rubbing two crystalline solid blocks of ice generates a large quantity of heat. Therefore there has an intimate relation between heat, and work, one can yield the other quantity. Energy is an extensive thermodynamics property like volume or surface area because it depends on the mass of the system. On the other hand properties like temperature, pressure, density, refractive index, etc are independent of the mass of the system. Therefore these are intensive property.
Units of Heat or Work
Physical quantities like heat, energy like potential or kinetic, and work derived or expressed in terms of base physical units or dimensions by multiplication or division. The unit and dimensions of quantities are the same and we can easily derive from the base unit. W = F × s, where force (F) = maas × acceleration and acceleration = length sec-2. Hence, W = mass length2 sec-2. Therefore, the CGS and SI unit of work or heat = gm cm2 sec-2 or simply erg and kg m2 sec-2 or simply joule respectively. Another most used unit for energies is calories, kilocalories, eV, liter-atmosphere, etc.
Heat Energy Conversion
Heat is also another form of energy that yielding or produces work. All the other forms like electrical, chemical, mechanical energy, etc completely change into work. But heat cannot completely convert into work. Any attempt to convert whole heat into work permanently changes the system or neighboring system. Another aspect of learning chemistry, when two objects with different temperatures come together, one with higher temperature losses heat, and the other gains it.
Production of Heat Energy
A liquid molecule freezes into solid yielding heat. Therefore, water freezes into ice producing specific heat.