Problem 101 - General Chemistry: Principles and Modern Applications

Question

Compared with its mass on Earth, the mass of the same object on the moon should be (a) less; (b) more; (c) the same; (d) nearly the same, but somewhat less.

Step-by-Step Solution

Answer

The mass of an object on the moon compared to its mass on Earth would be the same.

Step 1: Understand the Concept of Mass

The first step is to understand that an object's mass is a measure of the amount of matter in it. This quantity is intrinsic to the object and does not change regardless of where the object is in the universe.

Step 2: Understand the Effect of Location on Mass

The second step is to consider whether the location of an object would affect its mass. The answer is no, the location of an object has no impact on its mass, so if you moved it from the Earth to the moon, its mass would not change.

Step 3: Evaluate Each Option

In the third step, each option is evaluated based on the understanding of mass and location. (a) Mass will be less; This is incorrect as the mass of an object will not change regardless of location. (b) Mass will be more; This is also incorrect for the same reasons given above. (c) Mass will be the same; This is the correct answer. (d) Mass will be nearly the same but somewhat less; This is also incorrect. The mass of an object does not change within the universe.

Key Concepts

Intrinsic property

An intrinsic property is a characteristic of a substance that is independent of the quantity or size of the sample. Mass is considered an intrinsic property. It refers to the amount of matter contained in an object, and this quantity remains constant wherever the object might be in the universe.

Some other examples of intrinsic properties include:

• Density – the mass per unit volume of a substance.
• Boiling point – the temperature at which a substance changes from liquid to gas.
• Melting point – the temperature at which a substance changes from solid to liquid.

Understanding intrinsic properties is crucial as it helps us identify and describe materials comprehensively. For mass, it means that no external factors like location, shape, or external conditions will affect it. This concept is fundamental in physics and chemistry to differentiate it from other properties that might change under different circumstances.

Effect of location on mass

The mass of an object does not change with its location. Mass is the amount of matter in an object, and it's constant no matter where you take that object. Whether you place an object on Earth, the Moon, or even in outer space, its mass remains unchanged.

Here's why location doesn't affect mass:

• Mass is independent of external forces. It is not influenced by gravity, which can vary from planet to planet.
• Mass measures how much matter an object has, and this quantity doesn't shift by simply changing places.

Thus, the mass of an object is the same everywhere in the universe, unlike weight, which can vary with changes in gravitational forces. This is why an object weighs less on the moon due to its weaker gravity, but its mass remains the same.

Mass vs weight

While mass and weight are related concepts, they aren’t the same thing. Mass is the measure of matter in an object, whereas weight is the force exerted on that mass by gravity. This distinction is important in understanding why an object's state remains consistent across different environments.

Key differences between mass and weight:

• Mass is a scalar quantity that remains constant. It is measured in kilograms or grams.
• Weight is a vector quantity that changes with the gravitational field. It is measured in newtons.
• Weight can be calculated with the formula:

\[ \text{Weight} = \text{Mass} \times \text{Gravitational \ Acceleration} \]Thus, even though your weight would be less on the Moon compared to Earth because the Moon's gravity is weaker, your mass remains the same. This is because mass captures the inherent amount of matter, while weight is the gravitational pull on that matter.