विलयन Solution | Chap 02 | L 01| 12th NEET 2021-22 | New Regular Course | Chemistry | Vikram Singh

In chemistry, 'mole' is an essential tool for the chemical calculations. It is a basic SI unit adopted by the 14^(th) general conference on weights and measurements in 1971. A mole contains as many elementary particles as the number of atoms present in 12 g of ""^(12)C . 1 mole of a gas at STP occupies 22.4 litre volume. Molar volume of solids and liquids is not definite. Molar mass of a substance is also called gram-atomic mass or gram molecular mass. The virtual meaning of mole is plenty, heap or the collection of large numbers. 1 mole of a substance contains 6.022 xx 10^(23) elementary particles like atom or molecule. Atomic mass unit (amu) is the unit of atomic mass, e.g., atomic mass of single carbon is 12 amu. XL N_(2) , gas at STP contains 3xx10^(22) molecules. The number of molecules in x L ozone at STP will be

According to the Avogadro's law , equal number of moles of gases occupy the same volume at identical conditions of temperature and pressure. Even if we have a mixture of non-reacting gases then Avogadro's law is still obeyed by assuming mixture as a new gas. Now let us assume air to consist of 80% by volume of nitrogen (N_(2)) and 20% by volume of oxygen (O_(2)) . If air is taken at STP , then its 1 mol would occupy 22.4 L . 1 mol of air would contain 0.8 mol of N_(2) and 0.2 mol of O_(2) hence the mole fraction of N_(2) and O_(2) are given by X_(n_(2))=0.8, X_(o_(2))=0.2 If air is treated as a solution of O_(2) and N_(2) , then % w/w of oxygen is:

The amount of suga (C_(12)H_(22)O_(11)) required to prepare 2L of its 0.1 M aqueous solution is

The amount of sugar (C_(12)H_(22)O_(11)) required to prepare 22 L of its 0.1 M aqueous solution is: