☰
Atoms And Molecules
What is the utility of the mole concept?
Utility of mole concept.
(i) From the number of moles of a substance, we can calculate the number of elementary particles because the number of moles of a substance is directly proportional to the number of elementary particles.
(ii) One mole of a gas occupies 22.4 litres at S.T.P. (273 K and 1 atm).
(iii) One mole of any gas under the same conditions of temperature and pressure occupies the same volume.
(iv) One mole is equal to molecular mass in grams which is equal to 6.023 x 1023 atoms, molecules, ions etc. Thus, we can calculate absolute masses of atoms and molecules.
Sponsor Area
What is the mass of?
(a) 0.2 mole oxygen atoms.
(b) 0.5 mole of water molecules.
Calculate the number of molecules of sulphur (S8) present in 16 gm of solid sulphur.
Calculate the number of aluminium ions present in 0.56 gm of aluminium oxide.
Explain law of conservation of mass.
50 g of 10% lead nitrate is mixed with 50 g of 10% sodium chloride in a closed vessel. After the reaction has taken place, it was found that 6.83 g of lead chloride was precipitated. Besides, the reaction mixture contained 90 g water and sodium nitrate. Calculate the amount of sodium nitrate formed.
Name and explain two important laws of chemical combination ?
What are the postulates of Dalton’s atomic theory of matter?
Hydrogen and oxygen combine in two different ways to produce water and hydrogen peroxide. Which of Dalton’s law does this observation confirm? Explain.
State drawbacks of Dalton’s atomic theory of matter.
Sponsor Area
Sponsor Area