Answer :
The substance that cannot be broken down by a chemical reaction is argon. This is because the substance is an element, otherwise if this is a compound, then it can be still broken down by chemical means. Ammonia, methane and water are all compounds.
The substance that cannot be broken down by chemical reaction is [tex]\boxed{\left( 2 \right){\text{ argon}}}[/tex].
Further Explanation:
Substance is the pure form of matter while combination of atoms or molecules is termed as a mixture.
Types of substances:
1. Element
The simplest form of substance that cannot be further broken down by any chemical method is known as an element. Carbon, sulfur, and cobalt are some of the examples of elements.
2. Compound
When two or more different elements are held together by chemical bonds, compounds are formed. These can further be broken down into their respective constituents. Their properties are quite different from those of their constituent elements. NaCl, [tex]{\text{C}}{{\text{H}}_{\text{4}}}[/tex] and [tex]{{\text{H}}_{\text{2}}}{\text{O}}[/tex] are examples of compounds.
(1) Ammonia consists of one nitrogen and three hydrogen atoms so it is a compound. Therefore it can be broken down by chemical reactions.
(2) Argon is an element so it is the simplest form in which it can exist. Therefore it cannot be broken down by chemical reactions.
(3) Methane consists of one carbon and four hydrogen atoms so it a compound. Therefore it can be broken down by chemical reactions.
(4) Water consists of one oxygen and two hydrogen atoms so it is a compound. Therefore it can be broken down by chemical reactions.
Learn more:
- Which sample is a pure substance? https://brainly.com/question/2227438
- Which is a characteristic of a mixture? https://brainly.com/question/1917079
Answer details:
Grade: High School
Subject: Chemistry
Chapter: Elements, compounds, and mixtures
Keywords: substance, methane, argon, ammonia, water, element, compound, chemical reactions, broken down, simplest form, NaCl, CH4, carbon, sulfur, cobalt.
