A-level Chemistry AQA [New Spec] - Percentage Yield | A-level Chemistry | OCR, AQA, Edexcel

Percentage Yield in a Snap! Unlock the full A-level Chemistry course at http://bit.ly/2MdGoZJ created by Ella Buluwela, Chemistry expert at SnapRevise. SnapRevise is the UK’s leading A-level and GCSE revision & exam preparation resource offering comprehensive video courses created by A* tutors. Our courses are designed around the OCR, AQA, SNAB, Edexcel B, WJEC, CIE and IAL exam boards, concisely covering all the important concepts required by each specification. In addition to all the content videos, our courses include hundreds of exam question videos, where we show you how to tackle questions and walk you through step by step how to score full marks. Sign up today and together, let’s make A-level Chemistry a walk in the park! The key points covered in this video include: 1. What is % Yield? 2. Importance of % Yield 3. Limiting Reagents 4. Worked Example What is Percentage Yield? Gives us a measure of the effectiveness of a synthetic procedure. % Yield = Actual Yield / Theoretical Yield x 100%. Importance Tells us what % of our reactants have been converted into products. Indicates how successful our chemical reaction has been. % yield is not always 100%. Un-wanted by-products may be produced as a result of side reactions occuring. Some of the reactant may remain unreacted in the reaction vessel. Some product may be lost. Reaction may not proceed to completion as it is in equilibrium. Limiting Reagents In a reaction one chemical is often in excess. Surplus, More than enough to react, and some left over. The other chemical is the limiting reagent. It is not in excess, Dictates the amount of product that is produced. Limiting Reagents Recipe includes: 3 eggs, 100g flour, In the cupboard: 10 eggs, 1kg flour. Example Nitrogen and Hydrogen react according to the following equation to form Ammonia. 0.5g of Nitrogen and 0.6g of hydrogen are reacted together. Which is the limiting reagent?