91Ó°ÊÓ

a) A pure substance is matter which can not be separated by any physical or chemical action. There are twosorts of substance:
(1) Elements
(2) Compounds
An element could be a pure substance composed of just one style of material.
A compound is additionally a pure substance composed of the atoms of two or more elements. they're chemically combinedwithin the same proportion.

Silicon is part. A silicon ($Si$) chip is equipment. It consists of small crystals of Silicon (Si). it's composed of just one variety of material.
Therefore, a silicon ($Si$) chip is a part.

(b) oxide $\left({\mathrm{H}}_2{\mathrm{O}}_2\right)$ may be a strong oxidizer. it's a compound with an oxygen-oxygen covalent bond. it's composed of hydrogen and oxygen. they're chemically combinedwithin the same proportion.
Therefore, peroxide $\left({\mathrm{H}}_2{\mathrm{O}}_2\right)$could be a compound.

(c) Oxygen $\left({\mathrm{O}}_2\right)$ is part. it's represented by the symbol $\left({\mathrm{O}}_2\right)$. The number of oxygen is $8$, and it's placed in group $6A\left(16\right)$. it's a robust chemical agent. Therefore oxygen $\left({\mathrm{O}}_2\right)$isa part.

(d) Rust $\left({\mathrm{Fe}}_2{\mathrm{O}}_3\right)$is that the common name for iron oxide. Rust is corrosion, which occurs when oxygen combines with metal (Fe).
Therefore, rust $\left({\mathrm{Fe}}_2{\mathrm{O}}_3\right)$ may be a compound.

(e) Methane $\left({\mathrm{CH}}_4\right)$ could be a colorless and odorless gas. it's the most component offossil fuel.
Methane could be a simple alkane. it's acompound composed of carbon and hydrogen.
Therefore, methane $\left({\mathrm{CH}}_4\right)$ in fossil fuel may be a compound.