Question

What is one characteristic of a sample of matter that indicates it is a pure substance?

A) It can be separated using by a physical means, such as filtering.
B) The components in a pure substance do not have to be in definite ratios.
C) If the composition of a sample varies, the sample is a pure substance.
D) If the composition of a sample is fixed, the sample is a pure substance.

Answer 1

The answer is D) on USA Test prep

Step-by-step explanation:

Answer 2

A pure substance may be an element or a compound. It can be described as a substance that cannot be separated merely by physical means. A chemical change must occur. Also, it must have a definite ratio of individual elements if it is a compound to obey the Law of Definite Proportions. Thus, from the choices, the answer would be letter D.