Tag: chemical thermodynamics

Quizzes (7) Questions (120)

Questions Related to chemical thermodynamics

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

A well stoppered thermos flask contains some ice cubes. This is an example of:

  1. closed system

  2. open system

  3. isolated system

  4. non-thermodynamic system
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

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

Thus, a well stopped thermos flask containing ice an example for isolated system.

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

Which of the following is a path function?

  1. Internal Energy

  2. Enthalpy

  3. Work

  4. All of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Path functions are properties or quantities whose values depend on the transition of a system from the initial state to the final state. The two most common path functions are heat and work

A physical quantity is said to be state function if its value depends only upon the state of the system and does not depend upon the path by which this state has been attained. E.g pressure, volume, temperature

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

Which of the following statement is false?

  1. Work is a state function.

  2. Temperature is a state function.

  3. Change of state is completely defined when initial and final states are specified.

  4. Work appears at the boundary of the system.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

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

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

Which of the following are state property?

  1. Internal energy (U)

  2. Volume (V)

  3. Heat (q)

  4. Enthalpy (H)
Reveal answer Fill a bubble to check yourself
A,B,D Correct answer
Explanation

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.

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

Identify the state quantity among the following

  1. q

  2. q-w

  3. q+w

  4. q/w
Reveal answer Fill a bubble to check yourself
B,C Correct answer
Explanation

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.

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

Identify the state functions.

  1. $S$
  2. $q$
  3. $w$
  4. $q+w$
Reveal answer Fill a bubble to check yourself
A,D Correct answer
Explanation

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.

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

A closed vessel contains equal number of oxygen and hydrogen molecules at a total pressure of 740 mm. If oxygen is removed from the system, the pressure -

  1. Becomes half of 740 mm.

  2. Remains unchanged

  3. Becomes 1/9th of 740 mm.

  4. Becomes double 740 mm.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

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.

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

Assertion (A): All living systems are examples of a closed system. 

Reason (R): They cannot exchange matter and energy with their surroundings.

Choose the correct option.

  1. Both A and R are true and R is the correct explanation of A.

  2. Both A and R are true but R is not the correct explanation of A.

  3. A is true but R is false.

  4. Both A and R are false.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Living systems are open systems because they constantly exchange both matter (food, waste) and energy (heat, work) with their surroundings. Therefore, both the assertion and the reason are false.