Some basic concept of Chemistry - 3 for dmlt and paramedical student

              Properties of Matter 

                  The properties of matter are as follows:

(i) Mass and weight:
       Mass represents the amount of substance present in a system, while

      weight represents the force due to gravity exerted on that system.

Weight (W) = mass(m) x gravity(g)

(ii) Volume:
              It is the quantity of three-dimensional space enclosed by a matter.
                   Volume of different bodies are calculated differently,
e.g. for cuboidal body,

Volume (V) = length (1) x breadth (b) x height (h)

for a spherical body.
                . '. Volume =(4/3) π r3

(iii) Density:
        Density is defined as mass per unit volume.
It gives us an idea that how denser or rarer a matter is packed.
   Density (d) = mass (m)/volume (V)

(iv) Temperature :
                   Temperature of a body is the intensity of heat associated with it.

SI and NON-SI UNITS:

The metric system of measurement, the International system of units (SI Units), is widely used for quantitative measurements of matter in science and in most countries.
        However, different systems of measurement existed before the SI system was introduced.

       Any units used in other system of measurement (i.e. not included in the SI system of measurement), will be referred to as non-SI units.
In most science courses, non-SI Units are not be used regularly.

Introduction Non-SI units existed long before the invention of SI units. However, these units have been replaced by the standard SI Units in most countries.

 The countries that have continued to use non-SI units, such as the United States, keep these units mainly for economic, business, and cultural reasons. The following table will introduce some of the commonly used non-SI units, as well as their SI counterparts: