Copper is a widely used metal in various industries due to its excellent conductivity, malleability, and resistance to corrosion. Nitric acid, on the other hand, is a highly reactive and corrosive acid commonly used in the production of fertilizers, explosives, and dyes. When copper is exposed to nitric acid, it undergoes changes that can be classified as physical or chemical.
Physical changes refer to alterations in the physical properties of a substance without changing its chemical composition. When copper is exposed to nitric acid, it undergoes a physical change in the form of surface corrosion. The nitric acid reacts with the copper surface to form copper nitrate, a greenish-blue compound that covers the copper surface. This reaction can be represented by the following chemical equation: Cu + 4HNO3 → Cu(NO3)2 + 2NO2 + 2H2O The copper nitrate layer that forms on the copper surface is a physical change because it can be removed by washing or rubbing the copper surface.
Chemical changes, on the other hand, refer to alterations in the chemical composition of a substance. When copper is exposed to concentrated nitric acid, it undergoes a chemical change in the form of oxidation. The nitric acid reacts with the copper atoms to form copper nitrate, nitrogen dioxide gas, and water. This reaction can be represented by the following chemical equation: 3Cu + 8HNO3 → 3Cu(NO3)2 + 2NO + 4H2O The oxidation of copper by nitric acid is a chemical change because it results in the formation of new substances that cannot be easily reversed.
Applications of Copper and Nitric Acid
The physical and chemical changes that occur when copper is exposed to nitric acid have various industrial applications. Copper nitrate, the compound formed during the physical change, is used as a catalyst in the production of nylon, fertilizers, and other chemicals. Nitrogen dioxide, the gas formed during the chemical change, is used in the production of nitric acid and fertilizers. Copper, on the other hand, is used in the production of electrical wires, plumbing fixtures, and various other products.
Nitric acid is a highly corrosive and toxic substance that can cause severe burns and respiratory problems. When working with nitric acid, it is essential to wear appropriate protective equipment, such as gloves, goggles, and a respirator. The acid should also be stored in a cool, dry place away from flammable materials.
In conclusion, the exposure of copper to nitric acid results in physical and chemical changes that have various industrial applications. Understanding these changes is crucial in the production of various chemicals and products. However, it is essential to take appropriate safety precautions when working with nitric acid due to its highly corrosive and toxic nature.