Tag: basics of thermodynamics

Questions Related to basics of thermodynamics

Select the correct statements.

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. State of a system is assumed to be in internal equilibrium and the temperature and pressure are uniform throughout the system.

  2. Thermal drift in a system with time is more in Dewar flask than in insulated system.

  3. Thermal drift in a system with time is more in non-insulated system than in insulated system.

  4. Thermal drift in a system with time is more in insulated system than in non-insulated system.

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Correct Option: A,C
Which of the following is not a state function?
chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. Temperature

  2. Density

  3. Work

  4. Volume

  5. Pressure

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Correct Option: C
Explanation:

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.

Select the conditions which represent the criteria for spontaneity of a process in a closed system, from the following given conditions:


Serial Number Conditions
1. ${ \left( dG \right)  } _{ P,T }>0$
2. ${ \left( \Delta S \right)  } _{ universe }>0$
3. ${ \left( dU \right)  } _{ S,V }>0$
4. ${ \left( dH \right)  } _{ S,P }<0$
5. ${ \left( dS \right)  } _{ u,V }<0$
6. ${ \left( dS \right)  } _{ H,P }>0\quad $

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. 1 & 4

  2. 1 & 2

  3. 3 & 5 

  4. 4 & 6

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Correct Option: B

Which of the following factors is of no significance for roasting sulphide ores to the oxides and not subjecting the sulphide ores to carbon reduction directly?

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. Metal sulphides are thermodynamically more stable than $CS _2$

  2. $CO _2$ is thermodynamically more stable than $CS _2$

  3. Metal sulphides are less stable than the corresponding oxides

  4. $CO _2$ is more volatile than $CS _2$

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Correct Option: A
Explanation:

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. 

The reduction of metal oxides by carbon reduction process is spontaneous as $\triangle G$ for such a process is negative.
Thus $CO _2$ is more stable than $CS _2$ and the metal sulfides are more stable than the corresponding oxides.
Hence, factor listed in $(3)$ is of no. significance.

Which of the following is a state function and also an extensive property?

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. Internal energy

  2. Pressure

  3. Molar heat capacity

  4. Temperature

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Correct Option: A
Explanation:

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

Which of the following is not a thermodynamic state function?

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. Work

  2. Internal energy

  3. Free energy

  4. Temperature

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Correct Option: A
Explanation:

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