Saturday 4 July 2015

Assignment

                                                            Assignment
Q 1. Fill in the blanks.
(i)                  The number of radial nodes for 3p orbital is ----------.
(ii)                Number of angular nodes for 4d orbital is ----------.
(iii)              Total no of orbitals associated with third shell will be ------.
(iv)              Chlorine exists in two isotopic forms, Cl-35 and Cl-37 but its atomic mass is 35.5. This indicates the ratio of Cl-35 and Cl-37 is ---------.
(v)                Orbital angular momentum depends on -------.
(vi)              The total no of electrons having m=0 in Rb (atomic no. 37) -----.
(vii)            The total no of nodes in 3s orbital is ---.
Q 2.  Arrange s, p and d sub-shells of a shell in the increasing order of effective nuclear charge ( Zeff ) experienced by the electron present in them.
Q 3. Show the Distribution of electrons in oxygen atom (atomic no 8) using orbital diagram.
Q 4. Nickel atom can lose two electrons to form Ni2+ ion. The atomic number of nickel is 28. From which orbital will nickel lose two electrons?
Q 5. Which of the following orbitals are degenerate?    3dxy   ,4dxy , 3dz2, 4dyz, 4 dz2.
Q 6. Which of the following not show deflection from the path on passing through an electric field?
        Proton, cathode rays, electron, neutron.
Q 7. Wave lengths of different radiations are given below:
        A=300nm,   B = 300µm, C = 3nm, D =30 Å. Arrange these radiations in the increasing order of their energies.
Q8.  Match the following rules with their statements:
RULES
STATEMENTS
(i)                  Hund’s Rule
(a)    No two electrons in an atom can have the same set of four quantum numbers.
(ii)                Aufbau principle
(b)   Half-filled and completely filled orbitals have extra stability.
(iii)              Pauli Exclusion principle
      (c )  Pairing of electrons in the orbital belonging to the same subshell does not take place until each orbital is singly occupied.

(iv)              Heisenberg ‘s uncertainty principle
(d)               It is impossible to determine the exact position and exact momentum of a subatomic particle simultaneously.

(e)         In the ground state of atoms, orbitals are filled in the order of their increasing energies.

Q9. Two particles A and B are in motion. If the wavelength associated with particle A is 5x10-8m   calculate the wavelength associated with particle B if its momentum is half of A.
Q10. A moving electron has 4.55x10-25 J .What will be the wavelength of electron?
(Mass of electron = 9.1x10-31 kg and h= 6.6x10-34js).
Q11. Draw the shapes of the s, p and d orbitals and label it.
Q12. What is the angular momentum of an electron in (i) 2s orbital (ii) 4f orbital?
Q13. Calculate the wavelength for the emission transition if it starts from the orbit having radius1.3225 nm and ends at 211.6 pm. Name the series to which this transition belong and the region of the spectrum.
Q14. Indicate the no of unpaired electron in (a) P (b) Co (c) Cr (d) Fe (e) Rb .
Q15. With what velocity must an electron travel so that its momentum is equal to that of a photon of wavelength 560 nm?



Assignment class xi

Assignment: Basic concepts of Chemistry
Q .1 Define the following
Atomic mass, Gram atomic mass, Law of multiple proportion, Limiting reagent, Empirical formula, Molecular formula.
Q.2 Carbon is found to form two oxides, which contain 42.9% and 27.3% of carbon respectively. Show that these figures illustrate the law of multiple proportions.
Q.3 How many atoms and molecules of sulphur are present in 64.0 of (S8)?
Q.4 Calculate the mass of Na2CO3 which will have the same number of molecules as contained in 12.3 g of MgSO4.7H2O.
Q.5 Commercially available concentrated hydrochloric acid contains 38% HCl by mass.
(a) What is the molarity of this solution? The density is 1.19g/cm-3.
(b) What volume of concentrated hydrochloric acid is required to make 1.0 L of 0.10 M HCl?
Q.6 Calculate the molarities and normalities of the solutions obtained on mixing
(i) 100 mL of 0.2 M H2SO4 with 50 mL of 0.1M HCl
(ii) 100 mL of 0.2 N H2SO4 with 50 mL of 0.1M HCl
(iii) 100 mL of 0.1 M H2SO4 with 50 mL of 0.1M NaOH
(iv) 50 mL of 0.1 N H2SO4 with 100 mL of 0.1NaOH.
Q.7 A crystalline salt on being rendered anhydrous loses 45.6% of its weight. The percentage composition of the anhydrous salt is: Al = 10.50%, K= 15.1%, S = 24.96% and O = 49.92%
Find the simplest formula of the anhydrous and crystalline salt.
Q.8 1.0 g of a mixture of carbonates of calcium and magnesium gave 240 cm3 of CO2 at STP. Calculate the percentage composition of the mixture.
Q.9 A gas mixture of 3.0 litres of propane and butane on complete combustion at STP produced 10 L of CO2. Find out the composition of the gas mixture.
Q.10 1.5 g of chalk were treated with 10ml of  4N-HCl.The chalk was dissolved and the solution made to 100mL.25 mL of this solution required 18.75 mL of 0.2N- NaOH solution for complete neutralisation. Calculate the percentage of pure CaCO3 in the sample of chalk?


CHEMISTRY Stoichiometry Assignment Name: --------------------------------------------------------
1. Consider this balanced chemical equation: 2 NH3 (g) + SO3 (g) + H2O (l) -> (NH4)2SO4 (aq)
 Using proper chemical names for each species, write a sentence to show how this equation could be read in terms of moles.



 2. Carbon monoxide gas reacts with oxygen gas to produce carbon dioxide gas.
 (a) Write a balanced chemical equation for the reaction.
(b) How many moles of carbon dioxide gas should be produced when 4.25 moles of carbon monoxide gas react? 

(c) How many moles of carbon monoxide gas are required to react with 5.8 moles of oxygen gas?
3. Heat is used to decompose potassium chlorate into potassium chloride and oxygen gas.
 2 KClO3(s)à 2 KCl(s) + 3O2 (g) Calculate the number of moles of potassium chloride that should be produced from the complete decomposition of 51.2 g of potassium chlorate.

 4. This unbalanced equation represents the complete combustion of propane.
 __ C3H8 (g) + __ O2 (g) __ CO2(g) + __ H2O(g)
(a)   Balance the equation by providing the missing coefficients.
 (b) Calculate the mass of water that should be produced when 56.06 g of propane is reacted with excess oxygen.

 5. Cream of tartar (KHC4H4O6) and baking soda (NaHCO3) react to produce the carbon dioxide gas that makes cakes and muffins "rise". KHC4H4O6(aq) + NaHCO3(aq)à KNaC4H4O6(aq) + CO2(g) + H2O(l) If a baker uses 9.79 g of cream of tartar and 4.22 g of baking soda in a recipe for buns, which species is in excess and which is limiting. Justify your answer.

 6. Consider this equation for the production of copper:
 2 Al(s) + 3 CuSO4 (aq)à 3 Cu(s) + Al2 (SO4)3(aq)
 (a) Calculate the theoretical yield of copper that should be produced if 70.94 g of aluminium is reacted with excess copper (II) sulphate?
(b) If the actual yield of copper was 239.4 g, calculate the percent yield for this reaction.
 (c) Give 2 possible reasons why the actual yield is different than the theoretical yield.
 7. Aqueous solutions of calcium nitrate and sodium phosphate react to produce a precipitate.
 __ Ca(NO3)2( ) + __ Na3PO4( ) à __ Ca3(PO4)2( ) + __ NaNO3( )           
(a) Complete the equation for the reaction by providing coefficients and state of matter subscripts.
 (b) Calculate the mass of precipitate that should be produced if 72.05 g of dissolved calcium nitrate reacts with 48.88 g sodium phosphate.
 (c) Calculate the mass of the limiting reagent that remains after the reaction is complete.  


Saturday 14 September 2013

Electrochemistry

Solution

Solution : Homogeneous mixture of two or more than two pure substances.

Types of solution: on the basis of state of solution
1. Solid solution
2. Liquid solution
3.Gaseous solution

Expressing concentration of solution:
1. Molarity : The number of moles of solute present per litre of solution.
2. Molarity : The number of moles of solute present per 1000 g of solvent.
3. Mole fraction : Ratio of number of moles of components to the total moles of all the components in the solution.

Thursday 28 February 2013

Solid State


Matter exist in different states like solids, liquids, gases plasma etc. These states differ from each other due to difference in attractive forces and arrangement of constituent particles. Solid state the wide spread state of matter.

Haloalkanes and haloarenes

Introduction
Haloalkanes and haloarenes are the derivatives of aliphatic or aromatic hydrocarbon obtained by replacement of one or more hydrogen atoms by equal number of halogen atoms respectively.

Importance of haloalkanes ond haloarens 
1.Chloramphenicol is very effective in treatment of typhoid fever.
2.Chloroquine is used for the treatment of malaria fever.