Question

select the correct answer.
which statement best describes how a compound is different from an element?
a. a compound contains two or more elements in a fixed proportion.
b. a compound has a greater mass and volume than an element.
c. a compound has a definite shape, but an element does not.
d. a compound is a heterogeneous mixture, but an element is a homogeneous mixture.
e. a compound is one of several parts of an element.

Explanation:

• Option A: By definition, a compound is a substance formed when two or more elements are chemically bonded in a fixed proportion. This matches the key difference between compounds and elements.
• Option B: Mass and volume depend on the amount of substance, not on whether it's a compound or an element. So this is incorrect.
• Option C: The shape of a substance (definite or not) is related to its state of matter (solid, liquid, gas) and not to being a compound or an element. So this is wrong.
• Option D: Compounds are pure substances, not mixtures (heterogeneous or homogeneous), and elements are also pure substances. So this is incorrect.
• Option E: A compound is made of elements, not a part of an element. So this is wrong.

Answer:

A. A compound contains two or more elements in a fixed proportion.