Correct Answer - Option 1 : Equal number of molecules
The correct answer is Equal number of molecules.
Avagadro's law:
Avogadro proposed that:-
"Equal volumes of all gases at the same temperature and pressure should contain an equal number of molecules".
- Law means that as long as the temperature and pressure remain constant, the volume depends upon the number of molecules of the gas or in other words amount of the gas.
- E.g: If 1 liter of H2 contains x molecules, then 1 liter of O2/Cl2/ any other gas will contain equal molecules, under similar conditions of temperature and pressure.
- Avogadro made a distinction between atoms and molecules.
- Since the volume of a gas is directly proportional to the number of moles; one mole of each gas at standard temperature and pressure (STP) will have the same volume.
- i.e., one mole= Avagodro number of molecules (6.022 ×1023 molecules)
- Hence, at STP, 22.4 L of H2/O2/Cl2/ any other gas contains 1 mole of the substance or NA molecules (Avagadro no: of molecules).
- Mathematically, Avagadro's law is given by:
\(V \propto n\)
where "n" is the number of moles of the gas.
⇒ \({\text{V = K n}}\)
⇒ \(\frac{{{V_1}}}{{{n_1}}} = \frac{{{V_2}}}{{{n_2}}}\)
-
Atom: Smallest particle of an element that can take part in a chemical reaction; however it may or may not exist independently.
-
Molecule: Smallest particle of an element or a compound that can by itself. It never breaks up itself except for taking part in a chemical reaction.
-
Avogadro constant: It is known as the number of molecules in one mole of a gas that has been determined to be 6.022 ×1023.
-
At STP molar volume of an ideal gas or a combination of ideal gases is 22.4 L mol–1.
-
STP: Standard temperature and pressure mean 273.15 K (0°C) temperature and 1 bar (i.e., exactly 105 pascals) pressure.
