Tag: general introduction: importance and scope of chemistry

Hydrogen peroxide is formed when two atoms of hydrogen form a bond with two atoms of oxygen that have bonded to each other. Octane is a hydrocarbon consisting of hydrogen and carbon. Sodium bicarbonate (baking soda) can be produced from the reaction of carbon dioxide with an aqueous solution of sodium hydroxide, which creates sodium carbonate; it is then combined with carbon dioxide molecules to produce sodium bicarbonate. All the compounds are made up of different elements and have properties different from their constituent element.

All the above examples are mixtures and not compounds. Mixtures are impure substance made up of two or more pure substances. They are not chemically mixed and can be separated by physical means.

Antimony and Arsenic belong to the category of metalloids. A $metalloid$ is any chemical element which has properties in between those of metals and nonmetals, or that has a mixture of them.

In the given classification, the Tiger is not suitable as it is animal and all the others are plants.

Hydrogen peroxide $= H _2O _2$

Rose is not correctly classified as it is a plant, not mammal. Mammals are the types of animal.

Baking soda (sodium hydrogen carbonate $ \displaystyle (NaHCO _3)$ or sodium bicarbonate ) is a compound. It is formed by chemical combination of elements $Na, \ H, \ C, \ O $.

In the fourth period of periodic table there is filling of 4s,3d,4p orbitals. So the total number of orbitals to be filled $=1(4s)+5(3d)+3(4P)=9$