Use of Amount of Substance

Quantitative Chemistry

In this 90-minute course on Quantitative Chemistry, Dr Mark Read (University of Birmingham) introduces to the mathematics chemists use everyday to measure the amount of substance, pressures and volumes, percentage compositions and elemental analysis. We begin by: (i) defining the mole and Avogadro’s number; then (ii) moving on to define formula mass and how this is calculated using values from the periodic table; then (iii) understanding the term limiting reactant and how we can determine which reactants are in excess and which are limiting; before (iv) defining the term concentration of solution, and how this can be determined if we know the volume and amount of substance; then (v) looking at a experimental technique called a titration which is used to determine the concentration of an unknown solution; then (vi) defining atom economy and percentage yield, tools used to determine the efficiency and economy of a given reaction; before (vii) looking at in depth the ideal gas equation, the assumptions made when using and how it can be manipulated to our advantage; and finally (viii) defining and working through problems involving percentage composition.

Use of Amount of Substance

In the first mini-lecture, Dr Mark Read introduces using the amount of substance. Counting and grouping numbers of objects is used everywhere: in bakeries, office supplies, farms, so it stands to reason that chemists need some tool to group particles together. Here in this lecture, we are introduced to the mole, the fundamental unit of amount of substance, used to group together groups of small particles like molecules, atoms, photons, and subatomic particles like electrons and protons. We are introduced to Avogadro’s number and its origin, before moving on to a worked example.