Classify the following as pure substances and mixtures.
Brick, ice, hydrochloric acid, air

Pure Substance:- HCl(Hydrochloric Acid) , Ice
MIxtures:- Air, Brick

Pure substances are defined as substances that are made of only one type of atom or only one type of molecule (a group of atoms bonded together).

A mixture is a substance made by mixing severla substances together

Because brick made up of water nd mud ..air is also a homogenous mixture(oxygen,nitrogen etc)

HCl is a compound so pure substance, Ice is made up only water molecule so it is also a pure substance