Question

Define the term: system, surroundings, open system, closed system, isolated system, exothermic reaction, endothermic reactions, extensive and intensive properties.

Answer 1

Hint: All the terms mentioned here, which we have to define basically come under the basic concepts of thermodynamics.
Thermodynamics is that branch of science which deals with the study of different forms of energy and the relationship between them.
It explains, in particular, how thermal energy is transferred into and from other sources of energy and how it affects matter.

Complete answer:
Let us define each term one by one;
System: It is defined as that part of the universe which is under study and possesses fixed boundaries. These boundaries can be real or imaginary.
Surroundings : The rest of the universe (the entire universe other than the system) is referred to as surroundings.
Open system: The system which allows the exchange of both matter and energy with the surroundings is called an open system. For example: All living systems are open systems because they continuously exchange matter and energy with the surroundings.
Closed system: The system which allows the exchange of energy not of matter with the surroundings is called a closed system. In such a system the boundary is closed but the exchange of heat is possible. For example: heating of water in a sealed metallic container.
Isolated system: An isolated system is a system which can neither exchange matter nor heat with the surroundings. An isolated system is completely sealed having insulated boundaries. For example: hot water kept in a sealed and perfectly insulated thermos flask.
Intensive properties: The properties which do not depend upon the quantity of matter or substance present in the system. For example: Temperature, density etc.
Extensive properties: The properties which depend upon the quantity of matter or substance present in the system. For example: number of moles, mass, volume etc.
Exothermic reactions: The reaction which proceeds with the evolution of heat are called exothermic reactions. The enthalpy change for an exothermic reaction is always negative. For example:
${H_2}(g) + \dfrac{1}{2}{O_2}(g) \to {H_2}O(g)$ $\Delta H = - 247.0kJ$
Endothermic reactions: The reactions which proceed with the absorption of heat are called endothermic reactions. The change in enthalpy is always positive for an endothermic reaction. For example:
$2C(s) + {H_2}(g) \to {C_2}{H_2}(g);\Delta H = + 222.5kJ$

Note:Interactions between large ensembles of objects are observed and classified in thermodynamics.
-The notions of the thermodynamic system and its surroundings are central to this.
-A system consists of particles whose average motions determine their properties, and those properties are in turn connected by state equations to each other.
-Thermodynamics may be used with these methods to explain how systems respond to changes in their environment.