Some chemical notes for Medical students

Numbers And Quantities

Learning Objectives :
• To give an overview of some relevant units and numerical terms used in chemical analysis.
* Diagnostic Test :
moles, ancient and modern; Concentrations, weak and strong ; ppm and Dilution, all with a standard notation .

* The measurement of quantities in science have been standardized, although some older texts and lecturers still use old notations. We have included both in the text where appropriate.

* A mole is a made-up unit to describe such a huge number that it is difficult to write in text in ordinary notation with all its zeros. A mole was derived to try to overcome the difficulty of imagining such large numbers. A mole of particles is = 6 x 10*23 of them.

* The term is used when talking about the number of particles, atoms or molecules present in a material. You can have a mole of anything as it has no units of its own, so you can have a mole of oranges or of people. A mole has no units because it is a number, just like ‘12’ is a number - you can have 12 oranges or 12 people .
Logs to the base 10 are used to express the concentration of weak acid and alkaline solutions as a more easily understood whole number, pH .