Examkin

Question

Difficulty: HardDistinction Between Elements, Compounds, and Mixtures

During the fractional distillation of liquid air, nitrogen gas boils off at −196∘C-196^\circ\text{C} prior to oxygen gas at −183∘C-183^\circ\text{C} because liquid air is a homogeneous mixture whose constituent substances retain their individual physical properties.

Answer: Answer

Answer

The statement is TRUE.
Liquid air behaves as a physical mixture rather than a chemical compound. Consequently, its components retain their individual physical constants. Nitrogen boils off at −196∘C-196^\circ\text{C} before oxygen at −183∘C-183^\circ\text{C} during fractional distillation precisely because the mixture does not have a single fixed compound boiling point and its components maintain their independent identities.

Step-by-Step Solution

1
Classify liquid air as an element, compound, or mixture
Liquid air is a homogeneous mixture composed mainly of nitrogen (~78%) and oxygen (~21%) alongside small amounts of argon and other gases.
Distinguishing the classification of the matter is essential to determine its thermodynamic and physical behavior during separation.
2
Apply the fundamental property of mixtures regarding constituent properties
In a mixture, constituents retain their original individual physical and chemical properties because no chemical reaction or bond formation has occurred between them.
Chemical compounds undergo chemical combination resulting in entirely new properties, whereas mixtures retain component properties.
3
Evaluate the separation behavior based on boiling points
Because nitrogen retains its boiling point of −196∘C-196^\circ\text{C} and oxygen retains its boiling point of −183∘C-183^\circ\text{C}, warming liquid air causes the more volatile nitrogen to boil off first.
Fractional distillation relies directly on differences in the individual boiling points of components in a mixture.

Key Concept

Retention of individual physical properties by components of a mixture vs. chemical compounds
Estimated Time:1m 30s
Rate this question

Topics

Distinction Between Elements, Compounds, and Mixtures