System and surroundings - class-XI

In a closed system Matter is not exchanged but Energy is exchanged.

Solution:- (B) $q + w$

Given reactions are,

Both work and heat are path functions. Their values depends on the path chosen to reach a particular state.
However, the change in internal energy which is equal to the sum of heat and work, is a state function. Its value is independent of  the path chosen to reach a particular state.

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.

When some amount of water is in equilibrium with its vapour in a closed but non insulated vessel, then it will be an example of closed system.

State variables : To define a thermodynamics states of a system, we have to specify the values of certain mesurable quantities. These are called thermodynamic  variable or state variable. 
A system can be completely defined by four variables namely pressure, temperature, volume and composition. A system is said to be in a certain definite state when all of its properties have definite value. 
Between two fixed state the change in the value of state function is same irrespective of the path connection two states. 
Differential of a state function  integerated over a cyclic path returns zero. 
In other words summation of change in state function in a cyclic process is equal to zero.
Example : T, V, P and U (internal energy), H (enthalpy), S are state variables.

When we are warming ammonium chloride with sodium hydroxide in a test tube, there is exchange of heat as well as mass between system and surrounding. Mass is transferred from the open end of the test tube due to evaporation. Also heat is being exchanged through the walls of test tube.

State variables : To define a thermodynamics states of a system, we have to specify the values of certain mesurable quantities. These are called thermodynamic  variable or state variable.
A system can be completely defined by four variables namely pressure, temperature, volume and composition. A system is said to be in a certain definite state when all of its properties have definite value.
Between two fixed state the change in the value of state function is same irrespective of the path connection two states.
Differential of a state function  integerated over a cyclic path returns zero.
In other words summation of change in state function in a cyclic process is equal to zero.
Example : T, V, P and U (internal energy), H (enthalpy), S are state variables.

Work is not a state function. Work is a path function. Work depends on the distance or path followed by an object.

$\text{The theoretical yield was calculaterd incorrectly.}$

$\text{For spontaneous in neither direction:}$

State function is defined as a system that depends upon the initial and final positions,

In thermodynamics, a closed system can exchange energy (as heat or work) but not matter, with its surroundings. An isolated system cannot exchange any heat, work, or matter with the surroundings, while an open system can exchange energy and matter.

Rate of cooling=$\cfrac { dQ }{ dt } \propto \quad \Delta T$ 

A closed system is one which can only exchange energy. The entire universe is an isolated system because it has no surrounding. Hence it is a closed system.

A closed insulated container, a liquid is stirred with a paddle to increase the temperature, therefore it behave as adiabatic system, $q=0$

The second law of thermodynamics states that the entropy of an isolated system never decreases, because isolated systems always evolve toward thermodynamic equilibrium, a state with maximum entropy.

Let mass of hydrogen and oxygen be $100g$

$\triangle Q=\triangle U+ \triangle W$

$\Delta H=\Delta U+\Delta(PV)$

A thermoflask is designed to prevent the exchange of heat (energy) and matter with the surroundings, making it an isolated system. However, in many textbook contexts, if it is 'well-stoppered' but not perfectly insulated, it is often treated as a closed system regarding matter.

Answer $C: $Path, state.

An isolated system is a thermodynamic system that can not exchange either energy or matter outside the boundaries of the system.

Work is not a state function. It is path function. Its value depends on the path chosen to reach a particular state.

Internal energy, volume and enthalpy are state properties. Their values are independent of  the path chosen to reach a particular state.
Heat is a path function. Its value depends on the path chosen to reach a particular state.

Both work and heat are path functions. Their values depends on the path chosen to reach a particular state.
However, the change in internal energy is equal to the sum of heat and work. It is a state function. Its value is independent of  the path chosen to reach a particular state.

Both work and heat are path functions. Their values depends on the path chosen to reach a particular state.
However, the change in internal energy is equal to the sum of heat and work. It is a state function. Its value is independent of  the path chosen to reach a particular state.
Entropy is a state function.  Its value is independent of  the path chosen to reach a particular state.

An open system can exchange both matter and energy with surroundings. For example hot tea placed in an open cup constitutes an open system.

According to Dalton's Law of Partial Pressures, the total pressure is the sum of the partial pressures of the gases. If the number of molecules is equal, each gas contributes half the total pressure (370 mm each). Removing oxygen leaves only hydrogen, so the pressure becomes 370 mm, which is half of 740 mm.

A closed system can exchange energy with surroundings. It cannot exchange mass with surroundings. For example, hot tea placed in a cup which is covered with saucer constitutes a closed system.

$W$ and $q$ are not state functions

Path functions depend on the process taken to reach a state, not just the state itself. Work (W) and Heat (Q) are path functions, whereas internal energy, enthalpy (H), and Gibbs free energy (G) are state functions.

$\dfrac{p _1}{n _1}=\dfrac{p _2}{n _2}$ (As molecules of $N _2=$ molecules $O _2$)
($\therefore$ Moles $N _2=$moles $O _2$)
As $N _2$ molecules removed$=$ moles become half
$\dfrac{p _1}{1}=\dfrac{p _2}{1/2}$
$p=\dfrac{1}{2}p _1$
$\therefore$ Pressure reduced to half
$\therefore$ Answer is option C.

Types of system : 
(i)Closed system : A system which can exchange only energy with surrounding. 
(ii)Open system : A system which can exchange both energy and matter with surrounding. 
(iii)Isolated system : A system which cannot exchange matter or energy with surrounding.

$\triangle H$ depends on :

The change in enthalpy, $\Delta H$ accompanying a process does not depends on the path followed.
This is because the enthalpy of a reaction is a state function and its value depends on the inital and final states only.

State variables : To define a thermodynamics states of a system, we have to specify the values of certain mesurable quantities. These are called thermodynamic  variable or state variable. A system can be completely defined by four variables namely pressure, temperature, volume and composition. A system is said to be in a certain definite state when all of its properties have definite value.. Between two fixed state the change in the value of state function is same irrespective of the path connection two states.

A system which  cannot exchange matter and energy with the surroundings called isolated system.
A liquid in a sealed thermos flask and ice in a thermos flask are examples of isolated systems.

Work is a path dependent quantity. It is known as a path function.

$\Delta U$ and heat are state functions. Their values depends only on the state of the system and are independent of the path followed. Work is a path function. Its value depends on the path followed .

As we know,

The given statement is true.
 Internal energy change in a cyclic process is zero.
Internal energy is a state function. It depends only upon the initial and final states of the system and is independent of the path followed. Hence, for a cyclic process, the initial and final value of the internal energy is same.

Path functions are properties or quantities whose values depends on the transaction of a system from the initial state to the final state. The two most common path functions are heat and work.

A thermodynamic state function is a quantity whose value is independent of path. Thus, enthalpy is a state function.
Its value depends on iniital and final states and is independatn of path followed.

State functions are path Independent

The statement B is correct.
The change in altitude was the same for the train and the hikers, therefore the change in altitude is a state function. The value of state function depend only on initial and final value and is independent of the path followed.

The statement (C) BEST describes why work is a path function.
The amount of work varies depending on which path you take to get to the destination.
State function is independent of the pah followed whereas path function is dependent on path followed.

The term endothermic process describes a process or reaction in which the system absorbs energy from its surroundings so enthalpy change should be positive

An intrinsic property is a property of a system or of a material itself or within. It is independent of how much of the material is present and is independent of the form of the material. Heat flow is a results of a temperature difference between two bodies hence, it is not an intrinsic property of substance.

Two important examples of a path function are heat and work. These two functions are dependent on how the thermodynamic system changes from the initial state to final state.

In thermodynamics, a state function or function of state is a function defined for a system relating several state variables or state quantities that depends only on the current equilibrium state of the system. State functions do not depend on the path by which the system arrived at its present state. A state function describes the equilibrium state of a system.

For example, internal energy, enthalpy, Gravitational potential energy and entropy are state quantities because they describe quantitatively an equilibrium state of a thermodynamic system, irrespective of how the system arrived in that state.

In thermodynamics, a state function or function of state is a function defined for a system relating several state variables or state quantities that depends only on the current equilibrium state of the system. State functions do not depend on the path by which the system arrived at its present state. A state function describes the equilibrium state of a system.

Hence, work is a path function and not state function.

An isolated system is a thermodynamic system that cannot exchange either energy or matter (mass) outside the boundaries of the system. An isolated system differs from a closed system by the transfer of energy. Closed systems are only closed to matter, energy can be exchanged across the system's boundaries.
Hence, correct answer is option C. 

Solution:- (B) entropy and (C) free energy

Work is a path function and not a state function. The amount of work done is different for different paths although the initial and final states are the same. The amount of work depends on the path connecting the initial and final states.

$T _{1}=27°C=27+273=300 K$

Closed System - The system in which only energy can be exchanged with the surrounding.

In a closed system (For example, the presence of reactants in a closed vessel made of conducting material e.g copper) there is no exchange of matter, but exchange of energy is possible between system and the surroundings.

The pressure $(P)$, volume $(V)$, temperature $(T)$, amount $(n)$ etc. are the state variables or state functions.

partial pressure of $He$ in vessel $B$, 

For the reaction NH2COONH4(s) <=> 2NH3(g) + CO2(g), the initial equilibrium partial pressures are P(NH3) = 2p and P(CO2) = p, so total pressure P1 = 3p. After adding NH3, the new P(NH3) = 3p. Using Kp = (2p)^2 * p = 4p^3, the new equilibrium satisfies 4p^3 = (3p)^2 * P(CO2_new), giving P(CO2_new) = 4p/9. The new total pressure P2 = 3p + 4p/9 = 31p/9. The ratio P2/P1 = (31p/9) / 3p = 31/27.

Heat is a path function. The change of heat depends upon the path followed

This is a free expansion of an ideal gas into a vacuum. Since the system is isolated (q=0) and expands into a vacuum (w=0), the internal energy remains constant (delta U = 0). For an ideal gas, internal energy depends only on temperature, so the temperature remains 300K.

Temperature, density, volume and pressure are state functions.
They are intrinsic properties of the system. Their values  depend on initial and final state only and are independent of path followed.
On the other hand, work is a path function. It is not an state function. Its value depends on the path followed.

The reduction of metal sulfides by carbon reduction process is not spontaneous as the change in Gibb's free energy ($\triangle G$) for such a process is positive. 

$\Delta E=nCv\Delta T$ (depend on n)

Work depend as path, so it is a path function.