RPAL Theoretical Yield

Question 1

What is theoretical yield?

Accepted Answer

The maximum amount of product that can be formed from the limiting reagent

Answer

Theoretical yield is the calculated maximum product assuming all of the limiting reagent is converted to product with no losses.

Question 2

Which reagent is used to calculate theoretical yield?

Accepted Answer

The limiting reagent

Answer

Since the limiting reagent controls how much product forms, theoretical yield is always calculated from the limiting reagent's moles.

Question 3

In the reaction 2H₂ + O₂ → 2H₂O, if O₂ is the limiting reagent with 2 mol, what is the theoretical yield of H₂O?

Accepted Answer

4 mol H₂O

Answer

The 1:2 ratio of O₂ to H₂O means 2 mol O₂ produces 2 × 2 = 4 mol H₂O.

Question 4

What conversion is needed to express theoretical yield in grams?

Accepted Answer

Multiply moles of product by its molar mass

Answer

Converting moles of product to grams requires multiplying by the product's molar mass (g/mol).

Question 5

If the theoretical yield of a reaction is 50 g but only 40 g is collected, what does this indicate?

Accepted Answer

The reaction was less than 100% efficient — some product was lost

Answer

Collecting less than theoretical yield is normal; it indicates product loss due to side reactions, incomplete reaction, or handling errors.

RPAL - Reactants, Products, and Leftovers Practice Test