Chapter 5, Problem 91A

Interpretation Introduction

Interpretation:

The difference between homogeneous mixtures and compounds is to be determined.

Concept Introduction:

A material that is a mixture contains two or more separate chemicals. Elements and compounds both are considered pure substances. A material is considered an element if it is not subdivided into chemically simpler components. Mixtures can be homogeneous and heterogeneous.

Explanation of Solution

Chemical compounds differ from mixtures in that they are composed of a specified number of atoms in a chemical structure. For instance, H₂O is a combination with a constant proportion of oxygen to hydrogen. If the ratio changes, the water ceases to exist. Therefore, one says that a compound has a constant composition.

A mixture is said to be homogeneous if its composition remains the same throughout. For instance, blood is a homogeneous solution, as is a solution of sugar in water where the sugar is dissolved. Therefore, one will obtain the same composition whether one takes a sample of blood or a sugar-water solution.