Question

Which of the following statements are true for pure substances? (i) Pure substances contain only one kind of particles (ii) Pure substances may be compounds or mixtures (iii) Pure Substances have the same composition throughout. (iv) Pure substances can be exemplified by all elements other than nickel.

Answer 1

Answer:

The correct answer is (1) and (3).

Explanation:

Characteristics of pure substance:-

A pure substance contains only one type of particles which can either be atoms or molecules or elements or compounds.

A pure substance cannot be separated into other kinds of matter by any physical process but a mixture can as they are impure substances because they contain more than one particles. Ex: salt solutions.

A pure substance has fixed composition as well as fixed melting and boiling points. Ex: salt.

Pure substances cannot be exemplified by all elements other than nickel because pure nickel is an element containing only one kind of particles.

Answer 2

The correct option is (i) and (iii).

• The pure substance contains only one type of particle-like one type of atom, element or molecule.
• A pure substance cannot be a compound or mixture.
• A pure substance is made of one type of particle so, it has the same composition throughout.
• Pure substances can not be exemplified by all elements other than nickel because nickel has the same atoms throughout the element.