Which statement describes physical properties?

Which statement describes physical properties?

• A. A characteristic of a pure substance that can be observed without changing it into another substance
• B. A description of how a substance reacts or changes into a new substance
• C. The energy change during a chemical reaction
• D. The mass of a substance under standard conditions

Answer: (A)

Physical properties are characteristics you can observe or measure without changing the substance into something else. The statement describes exactly that: you can observe a feature of a pure substance without altering its identity. This is in line with what physical properties include—things like color, odor, density, melting point, or mass measured with a balance. In contrast, describing how a substance reacts to form a new substance points to chemical properties, since it involves a chemical transformation. Energy changes during a reaction are also tied to chemical changes. Mentioning mass under standard conditions introduces a measurement context rather than defining the property itself, so the clear, general idea of observing without changing the substance best captures what a physical property is.

Physical properties are characteristics you can observe or measure without changing the substance into something else. The statement describes exactly that: you can observe a feature of a pure substance without altering its identity. This is in line with what physical properties include—things like color, odor, density, melting point, or mass measured with a balance.

In contrast, describing how a substance reacts to form a new substance points to chemical properties, since it involves a chemical transformation. Energy changes during a reaction are also tied to chemical changes. Mentioning mass under standard conditions introduces a measurement context rather than defining the property itself, so the clear, general idea of observing without changing the substance best captures what a physical property is.