GCSE Chemistry - Atom Economy #31

Summary

This video explains the concept of atom economy, a measure used in industrial chemical reactions to quantify how efficiently reactants are converted into useful products. Using examples, it highlights how a low atom economy indicates that a large proportion of reactants turn into waste, as seen in hydrogen production. On the other hand, reactions like ammonia synthesis, with no waste products, have an atom economy of 100%. The video stresses the importance of atom economy for profitability, sustainability, and waste management, offering solutions like optimizing reactions or repurposing by-products.

Takeaways

• 🔬 Industrial chemical reactions often produce multiple products, but usually only one or two are useful.
• ♻️ In the reaction discussed, the goal is to produce hydrogen, while carbon dioxide is considered waste.
• 📊 Companies benefit from quantifying how much of the reactants are converted into useful products, known as atom economy.
• 🧪 Atom economy is calculated by dividing the relative formula mass of the desired product by the total formula masses of all reactants, then multiplying by 100.
• ⚗️ In the given example, hydrogen has an atom economy of 4.35%, meaning only a small portion of the reactants turn into useful products, with the majority being waste.
• 🌍 Reactions with low atom economies are less sustainable and less profitable, as raw materials are expensive and large amounts are wasted.
• 💰 Waste products can be costly to dispose of and harmful to the environment, making it essential to consider waste management.
• 🌱 One way to improve atom economy is to use more efficient reactions or find uses for waste products, turning them into valuable by-products.
• ⚖️ Atom economy is one factor in assessing profitability; others include percentage yield, raw material cost, reaction rates, and equilibrium positions.
• 🧫 An example of a reaction with 100% atom economy is the production of ammonia from nitrogen and hydrogen, where all reactants form the desired product.

Q & A

What is the primary aim of the reaction discussed in the script?

The primary aim of the reaction is to produce hydrogen as the useful product.

Why is carbon dioxide considered waste in this reaction?

Carbon dioxide is considered waste because it is not a desired product in this reaction, which only aims to produce hydrogen.

What is atom economy, and why is it important?

Atom economy is the percentage of reactants that are converted into useful products. It is important because it helps companies quantify the efficiency of a reaction, reducing waste and improving sustainability.

How is the atom economy calculated?

Atom economy is calculated by dividing the relative formula mass of the desired product by the total relative formula mass of all reactants, and then multiplying by 100 to get a percentage.

What is the atom economy of the reaction producing hydrogen in the script, and why is it considered low?

The atom economy of the hydrogen production reaction is 4.35%, which is considered low because only a small portion of the reactants are converted into the desired product (hydrogen), while the majority (95.65%) is waste.

Can atom economies be higher or lower than 4.35%, and what would be an example of a higher one?

Yes, atom economies can be higher or lower. For example, the reaction of nitrogen and hydrogen to form ammonia has an atom economy of 100% since all reactants are converted into the useful product, ammonia.

What are the three main reasons for considering atom economy in industrial processes?

The three main reasons are: 1) Raw materials are expensive, 2) It's less sustainable to use large quantities of reactants to make small amounts of products, and 3) Waste products are costly to dispose of and can harm the environment.

How can companies address the problem of waste in reactions with low atom economies?

Companies can use a more efficient reaction or find a use for the waste products, turning them into useful by-products instead of waste, which can save costs and reduce environmental impact.

Besides atom economy, what other factors are important in determining the profitability of a reaction?

Other important factors include the percentage yield, the cost of raw materials, the position of equilibrium, the rate of reaction, and the cost of maintaining the right conditions (such as temperature and pressure).

What is a potential advantage of turning waste products into useful by-products?

Even if the by-products can't be sold for much money, it is still more advantageous than paying for waste disposal, improving both profitability and sustainability.