Chapter U1.27, Problem 1TAI

Interpretation Introduction

Interpretation:

The processes used to extract an element from a compound are to be described.

Concept introduction:

Pure metals are very important in our lives. Most metals are found in combined state in nature. In ionic compounds, metals combine with nonmetals. One can extract pure metals from such ionic compounds by several methods.

Explanation of Solution

There are two main processes of extraction of metals from their ionic compounds.

1. Heating - Some metal compounds can be heated to very high temperatures to yield metals. For example wheniron (III) oxide is heated to very high temperatures in the presence of charcoal, the oxygen in the compound gets removed as carbon dioxide and solid iron is left behind. With the help of construction of better blast furnaces many metals were extracted by this method.
2. Electroplating - Electricity can also be used to extract metals from their compounds. For example copper can be extracted from a solution of copper sulfate by passing electricity through the solution. A simple circuit is set up with a battery connected to two nickel strips placed in a beaker of copper sulfate solution. Once the battery is hooked up one nickel strip acts as a positive terminal and other one acts a negative terminal. When the circuit is complete electrons move from negative to positive terminal. Copper sulfate dissociates into ions in the solution. Copper ions move towards negatively charged nickel strip and gains electrons to become elemental copper which then deposits as pure metal on the nickel strip. This process is called electroplating. In this way we can get pure copper from its compound.

Conclusion

Most metal atoms occur in nature in combined state with other atoms. Some metals can be extracted from their ionic compounds through heating and some can be extracted by using electricity to move electrons between atoms.