Mole concept & Avagadro's law

In Chemistry we have a unit that describes a quantity of particles. It is called the Mole(abbreviated as Mol).  A mole is 6.022×10²³  . The mole is a convenient unit. This number 6.022×10²³  is often referred as Avagadro's number.

Avagadro's law: states that equal volumes of different gases contain equal numbers of molecules at the same pressure and temperature.Thus , the number of hydrogen molecules in 1L is exactly same number of gas of carbon dioxide or any gas in 1L under the similar conditions.

 When the formula mass of ionic compound is determined by the addition of its component atomic masses and expressed in grams, it is called gram-formula mass or molar mass. An example is CaCO₃.

Example 1:

                                         1Ca = 40
                                          1C = 12
                                          3O = 48= 3 x16
                                    -----------------------
                                       CaCO_{3 = 100 Formula mass
                                                                        100g  = gram-formula weight or molar mass
The molar mass is equivalent to the mass of 1 mol of that material expresses in grams.}