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Difficulty: HardProperties of Matter

A sealed, rigid 250 mL250\text{ mL} container holds 50 g50\text{ g} of solid carbon dioxide (dry ice) at sea level on Earth. The container is transported to a research outpost on Mars, where surface gravity is approximately 38%38\% of Earth's gravity. During transport, the dry ice completely sublimates into carbon dioxide gas at room temperature inside the sealed container. Which statement correctly evaluates the physical and chemical properties of the carbon dioxide upon arrival at Mars?

  1. A
    Sublimation is a chemical change that forms a new gas compound, reducing the total mass of the sealed system while its weight remains constant.
  2. Sublimation is a physical change that conserves the 50 g50\text{ g} mass of carbon dioxide, while the weight of the substance decreases due to lower Martian gravity.Answer
  3. C
    Sublimation is a physical change, but the mass of the carbon dioxide decreases to 38%38\% of its Earth value because of the reduced gravitational field.
  4. D
    Sublimation is a chemical change where intramolecular bonds break into individual elements, causing both the mass and weight of the carbon dioxide to decrease.

Answer

Sublimation is a physical change that conserves the 50 g50\text{ g} mass of carbon dioxide, while the weight of the substance decreases due to lower Martian gravity.
The correct answer accurately states that sublimation (transition from solid directly to gas) is a physical change preserving the chemical identity of CO2CO_2. Because the container is sealed, the mass remains invariant at 50 g50\text{ g}. However, because Martian gravity is only 38%38\% of Earth's gravity, the weight (W=mgW = mg) decreases accordingly.

Step-by-Step Solution

1
Classify the phase change process (sublimation).
Sublimation is a physical change, not a chemical change.
Converting solid carbon dioxide to gaseous carbon dioxide changes only the physical state and arrangement of molecules, not their chemical composition.
2
Determine the mass of the substance in the sealed container on Mars.
Mass remains exactly 50 g50\text{ g}.
According to the Law of Conservation of Mass, matter is neither created nor destroyed in a closed system, and mass is an intrinsic property independent of gravity.
3
Analyze the effect of Martian gravity on the weight of the substance.
Weight decreases to approximately 38%38\% of its Earth value.
Weight is the gravitational force exerted on an object (W=mgW = mg), which is directly proportional to the local gravitational field strength.

Key Concept

Distinction between physical vs. chemical changes and mass vs. weight across varying gravitational environments
Estimated Time:1m 30s
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Topics

Properties of Matter

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