Question

(a) What is meant by (i) elements (ii) compounds, and (iii) mixtures ? Write down the names of two elements, two compounds and two mixtures.
(b) Classify the following into elements, compounds and mixtures Marble, Air, Gold, Brass, Sand, Diamond, Graphite, Petroleum, Common slat, Sea-water, Chalk

Answer 1

Explanation:

(a)(i) Elements have only one type of atom, so we cannot break down the element chemically, or physically. It can either exist as a molecule or as an atom. For example, nitrogen and argon.

(ii) Two or more dissimilar element’s atoms bind together to form a compound. So, by any chemical means, a compound can be broken down further into atoms. The properties of a compound are different from that of the elements of its components.

(iii) Two or more different compounds/elements combine to form a mixture. It has the properties of its components.

(b) Compounds – Chalk, common salt, marble .

Elements – Graphite, gold, diamond .

Mixtures – Petroleum, air, sea water, brass, sand .