Which substance can be decomposed by chemical means?
(1) ammonia (3) phosphorus
(2) oxygen (4) silicon



Answer :

Answer: (1) ammonia

Explanation: Ammonia [tex]NH_3[/tex] is a compound which is formed by the elements nitrogen and hydrogen in a fixed ratio by mass. It can be separated into its constituent elements by chemical means.

[tex]2NH_3\rightarrow N_2+3H_2[/tex]

Phosphorous (P), Oxygen (O) and Silicon (Si) are all elements and thus cannot be decomposed further.

[tex]\boxed{\left( 1 \right){\text{ ammonia}}}[/tex] is the substance that can be decomposed by chemical means.

Further Explanation:

The pure form of matter is defined as substance but the mixture is termed as the combination of atoms and molecules.

Classification of substances:

(a). Element

It is a type of pure substance and is the simplest form that cannot be broken down by any chemical means. Copper, iron, and aluminium are some of the examples of elements.

(b) Compound

It is composed of two or more different elements that are held together by chemical bonds. These can be decomposed into their respective constituents. Compounds have no similarity in properties with those of their constituent particles. NaCl, [tex]{\text{C}}{{\text{O}}_{\text{2}}}[/tex] and [tex]{\text{N}}{{\text{H}}_3}[/tex] are examples of compounds.

(1) Ammonia contains one nitrogen and three hydrogen atoms so it is a compound. Since compounds can be decomposed chemically, ammonia is also decomposed by chemical means.

(2) Oxygen (O) is an element so it is the simplest form in which it can exist. Therefore it cannot be decomposed by chemical means.

(3) Phosphorus (P) is an element so it is the simplest form in which it can exist. Therefore it cannot be decomposed by chemical means.

(4) Silicon (Si) is an element so it is the simplest form in which it can exist. Therefore it cannot be decomposed by chemical means.

Learn more:

  1. Give an example of a two-phase mixture: https://brainly.com/question/838401
  2. Which sample is a pure substance? https://brainly.com/question/2227438

Answer details:

Grade: High School

Subject: Chemistry

Chapter: Elements, compounds, and mixtures

Keywords: substance, ammonia, oxygen, phosphorus, silicon, element, compound, chemical means, decomposed, broken down, simplest form.

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