3.3.2 Atom Economy

In this lesson, we will explore the concept of atom economyA system in which consumers, producers, and government interact to produce, distribute, and consume goods and services., learn how to calculate it, and understand its significance in reaction design.

Atom Economy

Atom economy, also known as atom utilisation, quantifies the utilisation of atoms in a chemical reaction to produce desired products. A high atom economy indicates that a larger proportion of the starting materials is converted into useful products, minimising waste and maximising resource efficiency. Reactions with high atom economy are preferred for sustainabilityThe principle of meeting present needs without preventing future generations from meeting their own needs. and economic reasons.

Calculating Atom Economy

The percentage atom economy of a reaction is calculated using the balanced equation for the reaction. The formula for calculating atom economy is as follows:

Atom Economy = (Relative Formula Mass of Desired Product from Equation / Sum of Relative Formula Masses of All Reactants from Equation) × 100

Example Calculation

Let's consider an example:

In a reaction with the balanced equation:

2A + 3B → C + D

If the relative formula mass of the desired product C is 60 g/mol and the sum of the relative formula masses of reactants A and B is 100 g/mol, we can calculate the atom economy as follows:

• Atom Economy = (60 g/mol / 100 g/mol) × 100
• Atom Economy = 60%

Significance of Atom Economy

High atom economy signifies efficient use of starting materials and minimises waste production. Reactions with high atom economy are desirable for several reasons:

• Sustainable Development: High atom economy reduces the consumption of limited resources and minimises the generation of harmful waste products, promoting sustainable development.
• Economic Efficiency: Reactions with high atom economy are economically advantageous as they maximise the yield of desired products and minimise the costsThe sacrifices made when choosing a particular option, which may include money spent, time used, or resources consumed. associated with waste management.
• Environmental Impact: Reactions with high atom economy contribute to reducing the environmental impact by minimising waste generation and resource depletion.

Selecting Reaction Pathways

Atom economy is one of the factors considered when choosing a particular reaction pathway to produce a desired product. Reactions with high atom economy are favoured as they maximise the efficiency and sustainability of the process. Other factors such as yield, reaction rate, equilibrium position, and the usefulness of by-products also influence the choice of a reaction pathway.

Conclusion

Atom economy is a vital concept in chemistry that measures the efficiency of a reaction by determining the proportion of starting materials converted into useful products. Calculating and optimising atom economy is essential for sustainable development, economic efficiency, and reducing environmental impact. By understanding atom economy, we can make informed decisions about reaction design, selecting pathways that maximise the utilisation of resources and minimise waste generation.