Biophysics and Molecular Biology: Tools and Techniques by Pearson

Basic laboratory calculations

Mole concept

‘Mole’ is derived from the Latin word, which means ‘a mass.’ It is the SI unit for the amount of a substance, abbreviated as ‘mol’. 1 mole is equal to 6.022 × 10²³ particles. Particles may be atoms or molecules, or ions. This number is called Avogadro’s number. Hence, mole is a number. Just like a dozen means 12 objects, a mole means 6.022 × 10²³ objects. For example, a mole of oxygen is equal to 6.022 × 10²³ oxygen atoms. Similarly, a mole of glucose is equal to 6.022 × 10²³ molecules of glucose. Likewise, a mole of sodium carbonate (Na₂CO₃) is equal to 6.022 × 10²³ Na₂CO₃ units. Since Na₂CO₃ contains two sodium ions and one carbonate ion, therefore, a mole of Na₂CO₃ also contains 2 × 6.022 × 10^{23 ...}