Yield and Atom Economy Flashcards
Explain why its not always possible to obtain the calculated or expected amount of a product?
Incomplete Reactions:
The reaction might not go to completion. Some reactants may not fully convert into products. This is often the case with reversible reactions, where the system reaches equilibrium before all the reactants are used up.
Side Reactions:
Other reactions could occur, producing unwanted products. This means some of the reactants may be used up in side reactions, leaving less reactant to form the desired product.
Loss of Product:
During the experiment, some of the product might be lost. For example, when transferring liquids or filtering solids, some of the product may be spilled or left behind in the apparatus.
Impurities in Reactants:
If the reactants are not pure, there may be impurities that don’t react as expected, leading to a lower yield of the desired product.
Measurement and Experimental Errors:
Errors in measuring reactants or products (e.g., inaccurate mass or volume readings) can cause discrepancies between the theoretical and actual yield.
percentage yield formula
percentage yield= mass of product made/ max theoretical mass of product x 100
calculating theoretical mass
Molesofreactant=
Molarmassofreactant(g/mol)/Massofreactant(g)
describe atom economy as a measure of the amount of reactants that end up as useful products.
Atom economy is the percentage of the total mass of reactants that is converted into useful products. A high atom economy means more of the reactants are used to form the desired product, reducing waste and making the process more sustainable.
pecentage atom economy to form a desired product using the equation.
% atom economy= RFM of desired product / sum of RFM of all reactants x 100
explain why a particular reaction particularly in chosen to produce a speciified product, given appropriate data
The reaction should have a high atom economy, meaning most of the reactants are converted into the desired product with minimal waste. A reaction with high atom economy is more efficient and environmentally sustainable, as it minimizes the generation of unwanted by-products that require disposal.
Example: If you’re choosing a reaction to produce ethene from ethanol, the reaction should ideally produce only ethene with little or no waste, which ensures maximum efficiency.
The percentage yield is important to ensure the process produces the maximum amount of the desired product. High yield means that most of the reactants are converted into the product, leading to better use of resources and lower production costs.
Example: If a reaction is chosen to produce ammonia (NH₃) in the Haber process, the reaction conditions (temperature, pressure, and catalysts) are optimized to ensure a high yield of ammonia
