Was Calcium Oxide a Pure Substance?

Calcium oxide is a pure substance because it is a compound which consists of two elements, calcium and oxygen in a constant proportion, i.e., it has a constant composition.

Which of the following are pure substance?

Iron, steel, and water are some of the examples of a pure substance. Air may be a homogeneous mixture that's often considered to be a pure substance. As we know diamond, sucrose, honey, and air all are pure substances. Pure water has two hydrogens and one oxygen atom.

Which material is a pure substance?

All elements are mostly pure substances. A few of them include gold, copper, oxygen, chlorine, diamond, etc. Compounds such as water, salt or crystals, baking soda amongst others are also grouped as pure substances.