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The approximate composition of the atmosphere is shown in the pie-chart. Which stat...

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Problem

The approximate composition of the atmosphere is shown in the pie-chart. Which statement BEST describes the chart?

Answer

C

Step-by-step solution

  1. Analyze the Pie Chart: The pie chart displays the approximate composition of the Earth's atmosphere. It shows the percentages of different components: Nitrogen (80%), Oxygen (10%), Water vapor (5%), Inert gases (2.5%), and Carbon dioxide (2.5%).
  1. Understand the Components: The components listed (Nitrogen, Oxygen, Water vapor, Inert gases, Carbon dioxide) are all substances that make up the atmosphere. Nitrogen and Oxygen are elements, while Water vapor and Carbon dioxide are compounds. Inert gases are a group of elements.
  1. Define Mixture vs. Compound: A mixture is a substance comprising two or more components not chemically bonded. A compound is a substance formed when two or more chemical elements are chemically bonded together. A pure substance is a single element or compound.

4. Evaluate the Options:
* A. The chart shows the percentages of elements in a mixture. This is partially true, as Nitrogen and Oxygen are elements, but Water vapor and Carbon dioxide are compounds. Inert gases are elements. The atmosphere is a mixture, but not all components shown are elements.
* B. The chart shows the percentages of elements in a compound. This is incorrect. The atmosphere is a mixture, not a single compound, and it contains both elements and compounds.
* C. The chart shows the percentages of pure substances in a mixture. This statement is the most accurate. The atmosphere is a mixture. Each component listed (Nitrogen, Oxygen, Water vapor, Inert gases, Carbon dioxide) can be considered a pure substance in the context of its percentage contribution to the overall mixture. Nitrogen and Oxygen are elements (pure substances), and Water vapor ($H_2O$) and Carbon dioxide ($CO_2$) are compounds (pure substances). Inert gases are also elements.
* D. The chart shows the percentages of compounds in a pure substance. This is incorrect. The atmosphere is a mixture, not a pure substance, and it contains elements as well as compounds.