Question

1.what are the two classes of pure substance?

2.what is a pure substance?

Answer 1

Answer:

1) The two classes of pure substance are elements and compound.

2) Pure substance : 1) Any substance which is made up of one kind of particle is called pure substance.

2) It can't be separated into other substances by physical method.

3) It has it's own definite properties.

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Answer 2

Answer:

1. A pure substance has a constant composition and cannot be separated into  simpler substances by physical means. There are two types of pure substances: elements and compounds.

Elements: are pure substances made up of only l type of atom. Atoms of the same element are identical in properties.

2. Pure substances are substances that are made up of only one kind of particles and has a fixed or constant structure.

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