To determine the best classification for the sample of crude oil described in the table, let's analyze the types of hydrocarbons and their percentages.
The table shows:
- Paraffins: 30%
- Naphthenes: 49%
- Aromatics: 15%
- Asphaltics: 6%
1. Element: An element is a substance that consists of only one type of atom. The sample of crude oil contains multiple types of hydrocarbons, which means it is not composed of a single type of atom. Therefore, it cannot be classified as an element.
2. Pure Compound: A pure compound is a substance composed of two or more elements chemically combined in a fixed proportion. The crude oil sample contains different hydrocarbons with varying percentages. These hydrocarbons are mixtures of different molecules and are not chemically bonded in a fixed ratio. Thus, it cannot be classified as a pure compound.
3. Pure Substance: A pure substance has a uniform and definite composition. It can be either an element or a pure compound. Given the crude oil consists of multiple hydrocarbons in various percentages, it does not have a uniform composition that is characteristic of a pure substance. Hence, it is not a pure substance.
4. Mixture: A mixture is a physical combination of two or more substances where each substance retains its individual properties and can be present in any proportion. The crude oil sample fits this description since it contains paraffins, naphthenes, aromatics, and asphaltics in different percentages. Each of these hydrocarbons retains its individual properties and does not form a new chemical substance; they are simply mixed together.
Based on the analysis of the given information and definitions, the best classification for the sample of crude oil is:
a mixture.
