Mole concept

Here are some important numerical from the chapter mole concept.

  1. Calculate the volume of 320 g of SO2 at STP (atomic mass: S=32 and O=16)
  2. Calculate the volume of oxygen required for the complete combustion of 8.8 g of propane (C3H8) [atomic mass: C=12, O=16, H=1 ;molar volume= 22.4 dm3 at STP)
  3. Compute the moles of K3PO4 needed to produce 0.066 moles of KCl as per the equation:
    3CaCl2+ K3PO4 –>Ca3 (PO4)2+ 6 KCl [Ca=40, Cl=35.5, K=39, P=31, O =16]
  4. Compute the moles of HCl needed to form 0.35 mole of Cl2 with the following equation: 4HCl+ O2–>2H2O+2Cl2
  5. If 6 litres of hydrogen and 5.6 litres of chlorine are mixed and exploded, what will be the composition by volume of the resulting gaseous mixture?
  6. A solution of common salt when added to silver nitrate solution yields a precipitate of silver chloride which is 0.28 g in mass. Find the mass of sodium chloride in the solution and also the mass of sodium nitrate formed. [atomic mass: Na=23, Cl=35.5, N=14,O=16 , Ag=108]
  7. An organic compound with vapour density =94, contains C=12.67% , H=2.13% and Br=85.11%. Find its molecular formula. [atomic mass: C=12, H=1 , Br=80]
  8. An organic compound contains carbon, hydrogen, oxygen, nitrogen and chlorine. Find its empirical formula from the following data: C=56.71% ,H=4.72% , N=8.27% and 0.165 g of it gave 0.1397g of silver chloride. If the vapour density= 85, calculate the molecular formula. [C=12, H=1, N=14, Cl=35.5]
  9. Ammonia and oxygen combine to produce water vapour and nitric oxide according to the chemical equation: 4NH3+ 5O2–>6H2O+4NO

a)Write the chemical equation in terms of Gay Lussac’s law of combining volumes and the Avogadro’s law. How many moles of oxygen are required to burn 85 g of ammonia?

b)How many mole s of nitric oxide will be produced in reaction (a) ?

c)What is the volume of ammonia at STP that will oxygen in reaction (b)?


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  1. First of all, this website is helping me a lot!. It would be of great help if you have notes of hindi and computer

  2. Hey Roshini! We are glad to help you. Yes, we are soon going to be posting notes of those subjects as well. Good luck with your preparation!

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