the constituents of air are in a fixed proportion by mass
it cannot be represented with a chemical formula
the constituents of air can be separated by physical by physical means
none of the above
Explanation
Video Explanation
Post your Contribution
Discussions (18)
This question answer is actually A
the constituents of air are not in a fixed ratii by mass
A should be the correct option
This is because Air is a mixture of different gases, primarily nitrogen (78%) and oxygen (21%), with small amounts of other gases such as carbon dioxide, argon, and neon. The proportion of each gas in air is not fixed and can vary depending on the location and other factors.
For example, the amount of carbon dioxide in air can increase in areas with high levels of pollution, while the proportion of oxygen can decrease at high altitudes. Therefore, the composition of air is not in a fixed proportion by mass.
The correct answer is:
A. the constituents of air are in a fixed proportion by mass
This statement is actually false regarding the composition of air. The proportions of the constituents of air can vary slightly depending on factors such as location, altitude, and weather conditions.
The other options are correct and support the fact that air is a mixture:
- B. Air cannot be represented by a single chemical formula because it is a mixture of different gases.
- C. The constituents of air can be separated by physical means, such as fractional distillation or chromatography.
Therefore, option A is the correct answer.
A. the constituents of air are in a fixed proportion by mass
That’s the one that does not support air being a mixture.
Why:
1. Mixtures have *variable composition* — the amounts can change. Air is about 78% nitrogen, 21% oxygen, but that varies with altitude, humidity, pollution, etc.
2. Compounds have *fixed proportions by mass*, like water is always $H_2O$ with H and O in a 1:8 mass ratio.
Let’s check the others:
- B: Mixtures can’t be written as a single chemical formula. That supports it being a mixture.
- C: You can separate air by physical means like fractional distillation of liquid air. Compounds need chemical reactions to separate. So this also supports mixture.
So A is false for air, which means it doesn’t support the “air is a mixture” fact.
Whatsapp 0812 535 5537.
Mixtures vs. Compounds: In a mixture, the components are not present in a fixed ratio. Their proportions can vary depending on the source or location.
Variable Composition: The composition of air varies slightly due to factors like humidity, altitude, and pollution levels. Therefore, saying the constituents are in a "fixed proportion" describes a chemical compound, not a mixture.
Option A does not support the fact that air is a mixture because mixtures do not have constituents in fixed proportion by mass. The composition of air can vary depending on location and conditions (e.g., humidity, pollution). On the other hand, Options B and C support the idea that air is a mixture, since it cannot be represented by a chemical formula and its components can be separated by physical means. Hence, A is the correct choice because it incorrectly suggests a property of a compound rather than a mixture.
) the constituents of air are in a fixed proportion by mass: This statement is incorrect and contradicts the definition of a mixture. Air's composition can vary depending on location, humidity, and other factors.
B) it cannot be represented with a chemical formula: This is correct and supports the fact that air is a mixture.
C) the constituents of air can be separated by physical means: This is also correct and supports the fact that air is a mixture (e.g., fractional distillation of liquid air).
D) none of the above: This is incorrect since option A is a false statement
