Achemist is given a liquid sample of an unknown substance. the substance can't be separated into it's components by filtration, evaporation, distillation, paper chromatography, or any other physical means. the chemist then tries yo decompose the substance by a chemical change but can't. based on the chemist's results, which of the following best describes the unknown sample? a. elements b. mixture c. compound d. suspension

A) Elements

Explanation:

A mixture is a composite of two or more components that are combined physical and not through any chemical means. While a suspension is a mixture of a liquid and solid particles. Therefore, in both cases the components can be separated by some physical means.

A compound is a composite of two or more atoms which can be decomposed into simpler systems through chemical processes.

However, element is a single atom which can be neither be simplified any further by physical or chemical means.

"record the time to complete a chemical reaction" would most likely be part of a lab procedure.