Elements, Compounds and Mixtures

Question 1

Elements

Answer 1

An element is a pure substance that cannot be broken down into two or more simpler substances by chemical processes or electricity

Elements can be classified into two major groups: metals and non-metals

Question 2

Compounds

Answer 2

A compound is a pure substance which contains two or more elements chemically combined

Question 3

Mixtures

Answer 3

Mixtures are formed when two or more substances are added together without chemical bonds being formed

Question 4

Differences between a compound and mixture

Answer 4

Separation: The components of a mixture can be separated by physical methods while the elements in a compound can only be separated by chemical reactions or by using electricity

Properties: The chemical properties of a mixture are the same as those of its components while the physical and chemical properties of a compound are different from those of the elements in the compound

Energy changes: No chemical reaction takes place when a mixture is formed usually there is little or no energy change while a chemical reaction takes place when a compound is formed usually there is energy change

Composition: the components of a mixture can be mixed in any proportion while the elements in a compound are always combined in a fixed proportion

Melting and boiling point: a mixture has variable melting and boiling points while compound has fixed melting and boiling points