Theoretical Yield Flashcards

1️⃣ Familiarise yourself with the flashcards:

  • Look through all the flashcards to see what's on both sides.
  • Make sure you understand the information on each card. If something's unclear, click the link to the revision notes at the bottom of the page for more details.

2️⃣ Test yourself:

  • Look at the question or prompt on each card and try to remember the answer before flipping it over.
  • Check the answer and make a note of any cards you find challenging and need to go over more.

3️⃣ Consistently Review and Practice:

  • Use spaced repetition: spend more time on the cards you struggle with and go over them more often.
  • Regularly review all the flashcards to help you better understand and retain the information over time.

Note: We may include questions that have multiple correct answers. It's useful to remember specific examples to understand these concepts better.

PERSONALISED 1-TO-1 TUTORING

Need more help on this topic? Get 1-to-1 support

Get support with clear explanations, practice and feedback (Ages 5 to 16).

  • DBS-checked tutors
  • Flexible times
  • Parents can be updated

Want an ad-free experience? Subscribe to remove ads

What is meant by theoretical yield in a chemical reaction?

It is the maximum mass of product that can be made from the given amounts of reactants, worked out from the balanced equation.

Why is it called a "theoretical" yield?

It is a predicted amount, found by calculation. It is not the amount you actually collect in an experiment.

What key piece of information about a reaction do you need before you can calculate a theoretical yield?

You need the balanced symbol equation for the reaction.

What is the limiting reactant?

It is the reactant that is used up first and stops the reaction. It limits how much product can form.

Which reactant do you use to calculate the theoretical yield, and why?

You use the limiting reactant, because once it is all used up, no more product can be made.

What common formula links mass, moles and relative formula mass (Mr) when finding a theoretical yield?

moles (mol) = mass (g) ÷ relative formula mass (Mr).

What assumptions do we make when we calculate a theoretical yield?

We assume the reaction goes to completion, all of the limiting reactant reacts, and no product is lost.

How is theoretical yield different from actual yield?

Theoretical yield is the maximum mass predicted by calculation. Actual yield is the mass of product you really get in the lab.

List the main steps to calculate a theoretical mass of product from a known mass of a reactant.

1) Use moles = mass ÷ Mr to find moles of the limiting reactant. 2) Use the balanced equation to find moles of product. 3) Change moles of product to mass using mass = moles × Mr.

In the reaction 2H2 + O2 → 2H2O, if you have 4.0 mol of hydrogen and excess oxygen, what is the theoretical yield of water in moles?

4.0 mol of water, because 2 mol of H2 make 2 mol of H2O, so the ratio of H2 to H2O is 1:1.