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Thursday, October 27, 2011

9th chemistry Self-evaluation on Mole concept

Sample Problem 1. Calculate the number of mole in 52 g of Helium.
Solution. We know that, Atomic mass of He = 4u
So, its molar mass = 4 g  That is, 4 g of He contains 1 mole of He.
Or, 4 g of He = 1 mole of He
Or, 1 g of He = 1/4 mole of He
So, 52 grams of Helium =1/4 x 52 mole = 13 moles
Therefore, there are 13 moles in 52 g of He
Sample Problem 2. Calculate the number of moles for 12.044 X 1023 atoms of Helium.
Solution: 
6.022 X 1023 atoms of Helium           = 1 mole
1 atom of Helium                                 =1/6.022 X 1023 mole
12.044 X 1023 atoms of Helium         = [(1/6.022 X 1023) x  12.044 X 1023  ]moles
[ You may use  ----        Number of moles    = (given numbers of particles /Avogadro number)]
Sample Problem 3. How many moles are there in 5 grams of calcium?
Sample Problem 4. How many moles there in 12.044 X 1023 atoms of phosphorous?
Sample Problem 5. Calculate the mass of 0.5 mole of Nitrogen atoms.
Solution. We know that, Molar mass of of Nitrogen atoms 14 g
The mass of 1 mole of Nitrogen atoms = 14 g
The mass of 0.5 mole of Nitrogen atoms = 14x 0.5 g = 7 g
Alternate method,
                        Mass = Number of moles X Molar mass
                  Or,           = 0.5 X 14 = 7 g
Therefore, mass of 0.5 mole of N atoms is 7 grams.
Sample Problem 6. What is the mass of 3.011 X 1023 number of Nitrogen atoms?
Solution. We know that, Molar mass of of Nitrogen atoms 14 g
The mass of   6.022 X 1023 number of Nitrogen atoms= 14 g
The mass of  3.011 X 1023 number of Nitrogen atoms = [(14g/6.022 X 1023 )x 3.011 X 1023]g = 7 g
Sample Problems 
Sample Problem 7. Calculate the number of particles in each of the following:
(i) 0.1 mole of Carbon atoms  (ii) 46 grams of Sodium atoms.
Sample Problem 8 What is the mass of 4 moles of Aluminum atoms?
Determine the number of iron atoms in a piece of iron weighing 2.8 grams.
Sample Problem 9 If one mole of Carbon atoms weigh 12 grams, what is mass in grams of a single atom of Carbon?
Sample Problem 10. Calculate the mass of 0.5 mole of N2 gas.
Sample Problem 11. Convert 12.044 X 1022 molecules of Sulphur dioxide into moles?
Sample Problem 12. In which case the number of Hydrogen atoms is more- 2 mol of HCl or 1 mol of NH3?
Sample Problem 13 . An ornament of silver contains 20 gram silver. Calculate the moles of silver present.
Sample Problem 14. If 1 g sulphur dioxide contains x molecules, what will be the number of molecules in 1 g of methane?
Sample Problem 15. Calculate the number of aluminium ions present in 0.051 g of aluminium oxide.
Sample Problem 16. How many grams of neon will have the same number of atoms as 4 g of calcium?
Sample Problem 17. Calculate the number of iron atoms in a piece of iron weighing 2.8 grams.
Sample Problem 18. What is the mass of 3 moles of Zinc?
Sample Problem 19 : What is the ratio of molecules present in 6.6 grams of CO2 and 3.2 grams of SO2?

Sample Problem 20. If one gram of Sulphur contains x atoms, what will be the number of atoms in one gram of oxygen? (atomic mass of S = 32u) 
Useful stuff 

IX CBSE Chapter - Atoms and molecules E-Notes

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Empirical formula and molecular formula Study Notes

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Determining Empirical formula and molecular formula

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Empirical and molecular Formaula practice paper with solution

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Empirical formula worksheet

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Laws of chemical combination and Landolt Experiment

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YOU MUST VISIT THIS USE FULL LINK

9th chemistry Self-evaluation on Mole concept

Numerical based on mole concept

9th ChemistryAtoms and Molecules MCQ

Atoms and Molecules study material for Self study

Mole Concept and related solved Problem

9th Atoms and Molecules Downloads

IX Atoms and Molecules Guess Paper

NCERT Solution, MCQs, Study Notes, Q & A

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