Mass and weight

Mass and Weight 

Mass of a substance is the amount of matter present in it while weight is the force exerted by gravity on an object. The mass of a substance is constant whereas its weight may vary from one place to another due to change in gravity.

The mass of a substance can be determined to very accurately in the laboratory by using an analytical balance.

The SI unit of mass given as in in figure is kilogram however its fraction gram 1 Kg is equal to 1000 gram is used in Laboratories to the smaller amounts of chemicals used in chemical reactions.

Analytical balance

Volume:  volume has the units of length cube. So in SI system volume has units of M cube. But again in chemistry Laboratories commerce small volumes are used. Hens, volume is often denoted in centimetre cube or decimeter cube units.  

Are common unit litre which is not an SI unit is used for measurement of volume of liquids.

1 litre is equal to 1000 ml coma 1000 centimetre cube is equal to 1 decimeter cube

In the laboratory coma volume of liquids or solutions can be measured by graduated cylinder. A volumetric flask is used to prepare unknown volume of a solution the device is shown below.

Density:  density of a substance is its amount of mass per unit volume. So SI unit of density can be obtained SI unit of density is equal to SI unit of mass divided SI unit of volume is equal to kilogram metre per cube the unit is quite large and a chemist of an Express density in gram per centimetre cube where has mass is expressed in gram and volume is expressed in centimetre cube.