Different example of state, phase and component.
Different example of state, phase and component.
a
thermodynamic state
of a system is its condition at a specific time, that is fully identified by values of a suitable set of parameters known as state variables, state parameters or thermodynamic variables
given material or substance, the standard state is the reference state for the material's thermodynamic state properties such as enthalpy, entropy,
A phase is a form of matter that is homogeneous in chemical composition and physical state. Typical phases are solid, liquid and gas. Two immiscible liquids (or liquid mixtures with different compositions) separated by a distinct boundary are counted as two different phases, as are two immiscible solids.
In thermodynamics a
component
is a chemically-independent constituent of a system. The number of components represents the minimum number of independent species necessary to define the composition of all phases of the system.
For example - In water system the chemical composition of all the three phases is water. Hence it is one component system
Ice(s)↔Water(l)↔Vapor(g)
A system that contains water in the liquid state also contains hydronium cations and hydroxyl anions according to the reaction:
2 H
2
O ⇌ H
3
O
+
+ OH
−
The number of components in such a system is
3 chemical constituents - 1 chemical reaction - 1 constraint (charge neutrality) = 1. CaCO
3
- CaO - CO
2
system
This is an example of a system with several phases, which at ordinary temperatures are two solids and a gas. There are three chemical species (CaCO3, CaO and CO2) and one reaction:
CaCO
3
⇌ CaO + CO
2
.
The number of components is then 3 - 1 = 2
a
thermodynamic state
of a system is its condition at a specific time, that is fully identified by values of a suitable set of parameters known as state variables, state parameters or thermodynamic variables
given material or substance, the standard state is the reference state for the material's thermodynamic state properties such as enthalpy, entropy,
A phase is a form of matter that is homogeneous in chemical composition and physical state. Typical phases are solid, liquid and gas. Two immiscible liquids (or liquid mixtures with different compositions) separated by a distinct boundary are counted as two different phases, as are two immiscible solids.
In thermodynamics a
component
is a chemically-independent constituent of a system. The number of components represents the minimum number of independent species necessary to define the composition of all phases of the system.
For example - In water system the chemical composition of all the three phases is water. Hence it is one component system
Ice(s)↔Water(l)↔Vapor(g)
A system that contains water in the liquid state also contains hydronium cations and hydroxyl anions according to the reaction:
2 H
2
O ⇌ H
3
O
+
+ OH
−
The number of components in such a system is
3 chemical constituents - 1 chemical reaction - 1 constraint (charge neutrality) = 1. CaCO
3
- CaO - CO
2
system
This is an example of a system with several phases, which at ordinary temperatures are two solids and a gas. There are three chemical species (CaCO3, CaO and CO2) and one reaction:
CaCO
3
⇌ CaO + CO
2
.
The number of components is then 3 - 1 = 2
