The table shows the percentages of hydrocarbons that are found in a sample of crude oil.
| Hydrocarbons | Percentage |
|---|---|
| paraffins | 30 |
| naphthenes | 49 |
| aromatics | 15 |
| asphaltics | 6.0 |
Based on the given information, what is the best classification for this sample of crude oil?
A. an element
B. a pure compound
C. a pure substance
D. a mixture
Answer (1)
Crude oil contains various hydrocarbons: paraffins, naphthenes, aromatics, and asphaltics.
An element consists of one type of atom; a pure compound is a fixed ratio of elements.
A pure substance is either an element or a compound; a mixture combines substances physically.
Since crude oil contains multiple hydrocarbons, it is best classified as a mi x t u re .
Explanation
Analyze the problem We are asked to classify a sample of crude oil based on its composition of hydrocarbons. The options are: element, pure compound, pure substance, or mixture.
Identify the components Crude oil is composed of various hydrocarbons, including paraffins, naphthenes, aromatics, and asphaltics, as shown in the table.
Define the classifications An element is a pure substance consisting of only one type of atom. A pure compound is a substance consisting of two or more elements chemically bonded in a fixed ratio. A pure substance is either an element or a compound. A mixture is a combination of two or more substances that are physically combined but not chemically bonded.
Eliminate incorrect options Since crude oil contains multiple types of hydrocarbons (paraffins, naphthenes, aromatics, and asphaltics), it is not an element or a pure compound. Therefore, it cannot be a pure substance.
Determine the correct classification The presence of different hydrocarbons indicates that crude oil is a combination of multiple substances that are physically combined. Thus, the best classification for crude oil is a mixture.
State the final answer Based on the given information, the best classification for this sample of crude oil is a mixture.
Examples
Crude oil is a complex mixture of hydrocarbons used in many applications, such as fuel production and the manufacturing of plastics. Understanding its composition as a mixture helps in refining processes, where different hydrocarbons are separated based on their boiling points. For example, gasoline, kerosene, and diesel are all derived from crude oil through fractional distillation, a process that separates these components based on their different physical properties. Knowing that crude oil is a mixture allows engineers to optimize these separation techniques to obtain the desired products efficiently. This knowledge is crucial in the petroleum industry for resource management and product development.
