Advanced Topic 1091 of 1102 Biochemistry, Environment & Industry

Atom Economy

The fraction of reactant atoms that end in the desired product.

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In-depth explanation of Atom Economy

Atom economy is a measure of how efficiently a reaction incorporates the atoms of its reactants into the desired product. It is calculated as the molar mass of the desired product divided by the sum of the molar masses of all reactants, multiplied by 100 percent. Unlike percentage yield, which compares the product actually obtained with the theoretical amount, atom economy is a property of the reaction equation itself. Addition and rearrangement reactions can have 100 percent atom economy, while substitution and elimination reactions produce byproducts that lower it. Atom economy is a central metric in green chemistry.

Going deeper: Atom Economy

Key ideas: Atom economy equals molar mass of desired product over sum of molar masses of all reactants times 100 percent. Addition reactions and rearrangements can reach 100 percent, substitutions and eliminations are lower. Example: ethene plus water gives ethanol, 100 percent, while fermentation or chlorohydrin routes to ethene oxide are lower. Use the balanced equation with coefficients.

Common mistakes and connections: Mistake: confusing it with percentage yield, since atom economy is theoretical and independent of how well the experiment runs. Forgetting to include coefficients in masses, or counting a catalyst or solvent as reactants. Links to stoichiometry, green chemistry and E-factor.

Visualization of Atom Economy

Atom economy of two ibuprofen syntheses. The greener route puts more of the reactant atoms into the product and generates less waste. The interactive lesson shows this as a live animation or chart.

Worked example and use case

Adding hydrogen to ethene has 100 percent atom economy because all the atoms end up in ethane.

Frequently asked questions about Atom Economy

What is Atom Economy?

The fraction of reactant atoms that end in the desired product.

Is Atom Economy a beginner, intermediate or advanced topic?

Atom Economy is a advanced topic in Biochemistry, Environment & Industry. It builds on beginner and intermediate topics, so review those first if needed.

What should I learn before Atom Economy?

Study these earlier topics in Biochemistry, Environment & Industry first: Chemical Reactors, Process Safety, Green Chemistry in Industry.

What comes after Atom Economy?

The next topics in Biochemistry, Environment & Industry are History of Chemistry and Alchemy.

Can I practise Atom Economy with quizzes?

Yes. The interactive lesson includes a self-check question on Atom Economy, and the Biochemistry, Environment & Industry quiz draws on every topic in this area.

Where Atom Economy fits in Biochemistry, Environment & Industry

Atom Economy is topic 116 of 127 in Biochemistry, Environment & Industry.