Question

this is a flask containing nitrogen dioxide gas. in the atmosphere, nitrogen dioxide is a major pollutant. each molecule of nitrogen dioxide consists of one nitrogen atom chemically bonded to two oxygen atoms. at high temperatures, nitrogen dioxide decomposes to nitric oxide and oxygen gas. describe and classify nitrogen dioxide. nitrogen dioxide is composed of only one type of atom and cannot be chemically decomposed, so it is an element. nitrogen dioxide is composed of atoms of two or more different elements in a fixed ratio and can be chemically decomposed, so it is a compound. nitrogen dioxide is composed of two or more substances that can be physically separated and are evenly distributed, so it is a homogeneous mixture. nitrogen dioxide is composed of two or more substances that can be physically separated but are not evenly distributed, so it is a heterogeneous mixture.

Explanation:

A compound is a substance formed when two or more elements are chemically bonded together in a fixed ratio. Nitrogen dioxide (\(NO_2\)) has one nitrogen atom and two oxygen atoms chemically bonded. It can be decomposed chemically (as mentioned in the problem statement, decomposing to nitric oxide and oxygen gas at high temperatures). An element has only one type of atom. A homogeneous or heterogeneous mixture consists of two or more substances physically mixed (not chemically bonded), and can be separated physically. Since \(NO_2\) is chemically bonded from two elements (nitrogen and oxygen) in a fixed ratio and can be decomposed chemically, it fits the definition of a compound.

Answer:

Nitrogen dioxide is composed of atoms of two or more different elements in a fixed ratio and can be chemically decomposed, so it is a compound.