Question

Identify the correct statement regarding entropy (1) \Lambdat absolute zero of temperature, the entropy of perfectly crystalline substance is taken to be zaro. (2) At absolute zero of temperature, the cntropy of a perfoctly crystalline substance is taken to be zero. (3) At \(0^{\circ} \mathrm{C}\), the entropy of a perfoctly crystalline substance is taken to be zero. (4) \Lambdat absolute zcro of temperature, the entropy of all crystalline substances is taken to be zcro.

Short answer

Statement (2) is correct.

Step-by-step solution

Understand the Statements

Read through the given statements carefully and identify any scientific laws or principles that they might be referring to.

Recall the Third Law of Thermodynamics

Recall the Third Law of Thermodynamics, which states that the entropy of a perfectly crystalline substance approaches zero as the temperature approaches absolute zero.

Eliminate Incorrect Statements

Eliminate statements that contradict the Third Law of Thermodynamics. The law states that the entropy is zero for *perfectly crystalline* substances at absolute zero temperature, not at any other temperature like 0°C.

Verify the Correct Statement

Identify the statement that accurately reflects the Third Law of Thermodynamics. Statements (1) misspelled 'zero' as 'zaro'. Statement (3) incorrectly uses '0°C' instead of absolute zero. Statement (4) is incorrect because it says 'all' crystalline substances, which is not true. Statement (2) correctly reflects the law and uses the term 'perfectly crystalline'.

Key concepts

Third Law of Thermodynamics

The Third Law of Thermodynamics is a fundamental principle in physics and chemistry. It states that as the temperature of a perfectly crystalline substance approaches absolute zero, its entropy approaches zero. Entropy is a measure of the disorder or randomness in a system. At higher temperatures, molecules have more freedom to move, resulting in higher entropy. However, at absolute zero, the molecules are in their most ordered state, meaning entropy is at its lowest possible value. This law helps us understand why certain processes become impossible at very low temperatures. For example, reaching absolute zero is theoretically impossible due to the need for an infinite number of steps.
It's important to note that this law only applies to perfectly crystalline substances. Imperfections in a crystal structure mean the entropy will not reach zero even if the temperature is extremely low.

Crystalline Substances

Crystalline substances play a crucial role in understanding entropy, especially in the context of the Third Law of Thermodynamics. These substances have a well-ordered atomic structure, meaning the atoms or molecules are arranged in a highly regular pattern. Because of this regularity, it's possible to reach a state where the entropy is very low, particularly as the temperature approaches absolute zero.
Crystalline substances are not to be confused with amorphous substances, which lack a definite structure. The difference in structural order between these two types of materials leads to differences in their entropy levels. In a perfectly crystalline substance, the atomic arrangement is so regular and symmetrical that, at absolute zero, the system is in its most ordered state.
Examples of crystalline substances include diamonds, salts, and many metals like iron and aluminum.

Absolute Zero

Absolute zero is the lowest possible temperature where nothing could be colder and no heat energy remains in a substance. It is defined as 0 Kelvin (−273.15°C or −459.67°F). At this temperature, molecular motion comes to a theoretical standstill, and the entropy of a perfectly crystalline substance would be at its minimum value, which according to the Third Law of Thermodynamics, approaches zero.
Although scientists have come very close to reaching absolute zero, it remains unattainable in practice. This is because removing the last bit of heat from a system becomes increasingly difficult as the temperature approaches absolute zero. Despite this, the concept of absolute zero is essential for understanding thermodynamic processes and the behavior of materials at very low temperatures.
Absolute zero provides a baseline for temperature scales and helps in studying the properties of matter under extreme conditions. It serves as a critical reference point for various scientific fields, including physics, chemistry, and materials science.