--%>
Assignment Help - homework help

Avogadro's hypothesis Law Principle

Avogadro's hypothesis Law Principle- Berzelius, a chemist tried to correlate Dalton's atomic theory & Gay-Lussac's Law of gaseous volumes. According to his Berzelius hypothesis Equal volumes of all gases under similar conditions of temperature & pressure contain equal number of atoms e.g.

Hydrogen (1 vol) + Chlorine (1 vol)->HCl (2 vol)

Acc to Berzelius hypothesis:

Hydrogen (1/2 atom) + Chlorine (1/2 atom)->HCl (1 compound atom)

But this is indirect conflict of Dalton's atomic theory, so it was rejected.

So a new hypothesis was given by Avogardo.

According to him, An atom is a smallest particle of an element which can take part in a chemical reaction which may or may not be capable of independent existence.

A molecule is the smallest particle of an element or of a compound which have an independent existence. So the smallest particle of a gas is a molecule not an atom, so the volume of gas must be related to the number of molecules rather than atoms.

According to Avogrado's Hypothesis-Equal volume of all gases under similar conditions of temperature & pressure contain equal number of molecules. This is able to explain all the gaseous reactions & now known as Avogrado's Law or Avogrado's principle.

For example-

Hydrogen (1 vol) + Chlorine (1 vol)->HCl (2 vol)

By Avogrado's hypothesis:

n molecule+n molecule gives 2n molecule

1/2molecule of both [Hydrogen + Chlorine] ->HCl (1 molecule)

 Applications of this hypothesis-

(1)In the calculation of atomicity of elementary gases-Atomicity is defined as the number of atoms of the element present in one molecule of the substance e.g. atomicity of N2 is two & O3 is three.

(2)To find the relationship between molecular mass & vapour density of gas-(relative density)

Vapour density of gas=Density of gas/density of hydrogen

           =Mass of [certain vol of gas/same volume of H2] at STP

            =Mass of [n molecule of gas/ n molecule of H2] at STP

            =Mass of [1 molecule of gas/ 1 molecule of H2] at STP

 

                          Vapour density=Molecular Mass/2

(3)To find the relationship between mass & volume of gas-As the

Molecular Mass=Vapour density x 2

Or Molecular Mass=Mass of 22.4 L of gas at STP

Thus 22.4 L of any gas at STP weight is equal to the molecular mass of the gas expressed in grams which is called Gram-Molecular Volume Law (G.M.V.).

   Related Questions in Chemistry

  • Q : Partial vapour pressure of volatile

    Choose the right answer from following. For a solution of volatile liquids the partial vapour pressure of each component in solution is directly proportional to: (a) Molarity (b) Mole fraction (c) Molality (d) Normality

    		•
  • Q : Molarity of Nacl solution When 5.85 g

    When 5.85 g of NaCl (having molecular weight 58.5) is dissolved in water and the solution is prepared to 0.5 litres, the molarity of the solution is: (i) 0.2 (ii) 0.4 (iii) 1.0 (iv) 0.1

    		•
  • Q : Reactivity of allyl and benzyl halides

    why allyl halide and haloarenes are more reactive than alkyl halide towards nucleophilic substitution

    		•
  • Q : Describe First Order Rate Equation The

    The integrated forms of the first order rate equations are conveniently used to compare concentration time results with this rate equation. Rate equations show the dependence of the rate of the reaction on concentration can be integrated to give expressions fo

    		•
  • Q : Problem on Osmotic Pressure of solution

    The osmotic pressure of a 5% solution of cane sugar at 150oC  is (mol. wt. of cane sugar = 342)(a) 4 atm (b) 3.4 atm (c) 5.07 atm (d) 2.45 atmAnswer: (c) Π = (5 x 0.0821 x 1000 x 423)/(342 x 100) = 5.07 atm

    		•
  • Q : Explain polyhalogen compounds with

    Carbon compounds containing more than one halogen atom are called polyhalogen compounds. Most of these compounds are valuable in industry and agriculture. Some important polyhalogen compounds are described as follows:

    Q : Why acetic has less conductivity than

    Illustrate the reason, why acetic has less conductivity than Hcl?

    		•
  • Q : What are Vander Waal's Radii? Vander

    Vander Waal's radii can be assigned to the atoms of molecules on the basis of the closeness of approach of these atoms in crystalline substances. Diffraction studies of crystals give information about hoe molecules can approach each other and can pack

    		•
  • Q : Mole fraction Give me answer of

    Give me answer of following question. The sum of the mole fraction of the components of a solution is : (a) 0 (b) 1 (c) 2 (d) 4.

    		•
  • Q : Various cons of eating the organic foods

    Describe the various cons of eating the organic foods? Briefly illustrate it.

    		•