Reagent

Determining the Limiting Reagent and Excess Reagent using Stoichiometry.

This video looks in detail at the use of 2,4-dinitrophenylhydrazine (Brady's reagent) to identify specific aldehydes and ketones. It examines the mechanism and demonstrates the practical procedure.

Limiting reactant is also called limiting reagent. The limiting reactant or limiting reagent is the first reactant to get used up in a chemical reaction. Once the limiting reactant or limiting reagent gets used up, the reaction has to stop and cannot continue. After the limiting reactant or limiting reagent is used up and the reaction stops, there is extra of the other reactants left over. Those are called the excess reactants. In this video, we'll first learn about limiting reactant and limiting reagent by comparing chemical reactions to cooking recipes. We'll look at how to calculate limiting reactant and limiting reagent using cooking ingredients, and then looking at an actual stoichiometry problem,

This video looks in detail at the three common tests used to distinguish between aldehydes and ketones. They all work on the basis that aldehydes can behave as reducing agents while ketones cannot. 1. Fehling's solution. 2. Tollen's reagent. 3. Acidified potassium dichromate.

A short video to show you the setup for the organic practical technique known as "reflux distillation" using a 2-necked flask. This allows the second reagent to be added slowly (or in stages) after the apparatus has been safely assembled. It is one in a series of short videos looking at the main organic practical techniques: heat & distill; reflux distillation; washing and drying in solvent extraction; recrystallisation and melting point determination; and others

We'll practice limiting reactant and excess reactant by working through a problem. These are often also called limiting reagent and excess reagent. The limiting reactant or the limiting reagent is the first reactant to be used up during a chemical reaction. Once the limiting reactant or limiting reagent is used up, no more product can form. In order to solve stoichiometry problems with limiting reactant or limiting reagent, we need to figure out which of the reactants is the limiting reactant or limiting reagent. Then, we see how much product can be formed by using the maximum amount of the limiting reactant or limiting reagent. The excess reactant or excess reagent is what is left over after all of the limiting reactant or limiting reagent has been used up.