An electric device delivers a current of [tex]$15.0 A$[/tex] for 30 seconds. How many electrons flow through it?
Answer (2)
To find how many electrons flow through a device with a current of 15.0 A for 30 seconds, we calculate the total charge as 450 C and then convert this charge into the number of electrons, resulting in approximately 2.81 x 10^21 electrons.
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Crude oil consists of different hydrocarbons: paraffins, naphthenes, aromatics, and asphaltics.
An element is a pure substance with only one type of atom.
A pure compound consists of elements chemically bonded in a fixed ratio.
A mixture is a combination of substances physically combined, not chemically bonded.
Therefore, the best classification for crude oil is ami x t u re .
Explanation
Analyze the problem and data The problem provides the composition of a crude oil sample in terms of the percentages of different hydrocarbons: paraffins (30%), naphthenes (49%), aromatics (15%), and asphaltics (6.0%). The question asks us to classify the crude oil sample as either an element, a pure compound, a pure substance, or a mixture.
Define the classifications Let's define each of the possible classifications:
Element: A pure substance consisting of only one type of atom (e.g., gold, oxygen).
Pure compound: A substance consisting of two or more elements chemically bonded in a fixed ratio (e.g., water, carbon dioxide).
Pure substance: A substance with a fixed composition and distinct chemical properties. This can be either an element or a pure compound.
Mixture: A combination of two or more substances that are physically combined but not chemically bonded. Mixtures can be homogeneous (uniform composition) or heterogeneous (non-uniform composition).
Determine the correct classification Crude oil is composed of various hydrocarbons, including paraffins, naphthenes, aromatics, and asphaltics, each with different chemical structures and properties. Since the crude oil sample contains multiple types of hydrocarbons that are not chemically bonded, it cannot be classified as an element, a pure compound, or a pure substance. Instead, it is a combination of different substances.
State the final classification Based on the composition of the crude oil sample, the best classification is a mixture , as it consists of different hydrocarbons physically combined.
Examples
Understanding the composition of mixtures is crucial in many real-world applications. For instance, in the food industry, knowing the precise mixture of ingredients in a product ensures consistent taste and quality. Similarly, in environmental science, analyzing the mixture of pollutants in air or water helps in identifying sources and developing effective remediation strategies. In the context of crude oil, understanding its hydrocarbon composition is essential for refining processes, allowing us to separate and utilize different components for various applications like fuels, plastics, and lubricants.
