In which case is no work done?
Let us consider some cases where work is not done: Work is zero if applied force is zero (W=0 if F=0): If a block is moving on a smooth horizontal surface (frictionless), no work will be done. Note that the block may have large displacement but no work gets done. Work is zero if Cos θ is zero or θ = Π/2.
Why is no work done in free expansion?
When a free expansion takes place, there is no external pressure acting on the gas, which makes the gas expand. Since external pressure is zero, the work done during the free expansion is zero. So the correct answer to the question is option (B)-Zero.
In which process net work done by the gas is zero?
isochoric process
In which thermodynamic process is no work done?
Why there is no work done if the volume is constant?
The work done is the area under the curve for the process. Because there is no area under the curve in a constant-volume process the work done by the gas is zero: . Key ideas for a constant-volume process: There is no work done by the gas: . The heat added to the gas is equal to the change in internal energy: .
In which process net work done is not zero?
adiabatic process
What is the first law of thermodynamics example?
According to the first law of thermodynamics, energy can be transferred from place to place or changed between different forms, but it cannot be created or destroyed. For instance, light bulbs transform electrical energy into light energy, and gas stoves transform chemical energy from natural gas into heat energy.
What is an example of isobaric process?
An everyday example of an isobaric process is boiling water in an open container. By supplying heat energy to the water, it rises in temperature and turns into steam. The steam obtained has a higher temperature and occupies a greater volume, however, the pressure remains constant.
Is work a state function?
Heat and work are not state functions. Work can’t be a state function because it is proportional to the distance an object is moved, which depends on the path used to go from the initial to the final state. Thermodynamic properties that are not state functions are often described by lowercase letters (q and w).
Which is the state function?
A state function is a property whose value does not depend on the path taken to reach that specific value. In contrast, functions that depend on the path from two values are call path functions. Both path and state functions are often encountered in thermodynamics.
Why work is not a property?
Work is not a property of a system. Work is a process done by or on a system, but a system contains no work. This distinction between the forms of energy that are properties of a system and the forms of energy that are transferred to and from a system is important to the understanding of energy transfer systems.
Which is not state function?
Heat and work are not state functions. Work can’t be a state function because it is proportional to the distance an object is moved, which depends on the path used to go from the initial to the final state.
Why Heat is not a state function?
A state function is independent of pathways taken to get to a specific value, such as energy, temperature, enthalpy, and entropy. Enthalpy is the amount of heat released or absorbed at a constant pressure. Heat is not a state function because it is only to transfer energy in or out of a system; it depends on pathways.
Which out of the following is not state function?
Work is not a state function as during a process its value depends on the path followed. The value of enthalpy, internal energy entropy depends on the state and not on the path followed to get that state, hence these are state functions.
Why Q W is a state function?
E = q+w. it is a state function as it depends on the intial and final state and independent of the path.
Is QW a path function?
Path function: Their magnitudes depend on the path followed during a process as well as the end states. Work (W), heat (Q) are path functions. Point Function: They depend on the state only, and not on how a system reaches that state. All properties are point functions.
What does Hess’s law state?
Hess’s law, also called Hess’s law of constant heat summation or Hess’s law of heat summation, rule first enunciated by Germain Henri Hess, a Swiss-born Russian chemist, in 1840, stating that the heat absorbed or evolved (or the change in enthalpy) in any chemical reaction is a fixed quantity and is independent of the …
Is UV a state function?
PV is itself a state function, not a path one. No matter how a system gets to a particular Pressure and Volume, the value PV will always be the same; it is a function only of the state variables P and V. It is simply p times V, pressure times volume, which are both state variables.
What is the difference between state and path function?
A state function is a property describes a particular state, without depending on the path taken to reach this state. In contrast, functions whose value depends on the path taken to get between two states are called path functions.
Is free energy a state function?
The Gibbs free energy of a system at any moment in time is defined as the enthalpy of the system minus the product of the temperature times the entropy of the system. The Gibbs free energy of the system is a state function because it is defined in terms of thermodynamic properties that are state functions.
What is the difference between state variable and state function?
Any change in these properties will change the state of a system and these properties are called state variables. Some state variables depends only on the initial and final state but not the path or process how it is carried out and they are called state function.