One difference between mixtures and pure substances is that

The mixture is made up of different atoms and pure substance is made up of same type of atom.

The main difference is that mixture can be separated into its component by physical mean while pure substances can not be separated by physical process

Explanation:

Mixture:

The properties of the mixture are not same and contains the properties of all those component present in it.it is a combination of one or more Pure substances and can be separated by simple physical methods.it have varying boiling and melting point

Examples are:

mixture of salt and sandSalt water is mixture of water and NaCl and can be separated by physical mean.Alloys: its a mixture of different metalAir: mixture of gases

Pure Substance:

Pure substances are those made of same type of atoms all elements and compounds are pure substances.

it can not be separated by simple physical meanit have very constant and consistent melting and boiling point

Examples are:

Water : contain only water moleculeAll elements: all elements are pure substance made of same atomsAll compounds: can not be separated by physical mean.

It is 4.92 e-4 sorry if i am wrong

The correct answer is weight.