LONG ANSWERS PART ONE
Q. 1 (a) What are isotopes? Write a note on relative abundance and occurrence of isotopes.
(b) What is mass spectrometer? How is it used to determine the relative atomic masses of isotopes?
Q. 2 (b) What is empirical formula? Write down the steps involved in determination of empirical formula.
(b) What is stoichiometry? Give its assumptions. Mention two important laws, which help to perform the stoichiometric calculations.
Q. 3 (a) What is a limiting reactant? How does it control the quantity of the product formed? Explain with examples.
(b) What is the difference between actual yield and theoretical yield? Why actual yield is less than theoretical yield?
Q. 4 (a) What is general gas equation? Derive its various forms.
(b) State Dalton's law of partial pressure. Also give its applications.
Q. 5 (a) State and explain Graham's law of diffusion of gases.
(b) Give postulates of kinetic molecular theory of gases (KMT).
Q. 6. (a) How volume and pressure are corrected by Van der Waal's equation?
(b) What is plasma? How is it formed? Explain its various types.
Q. 7 (a) Define hydrogen bonding. Explain hydrogen bonding in NH3, H2O and HF, how is it helpful in explaining the structure of ice?
(b) What is vapour pressure of a liquid? Describe measurement of vapour pressure by manometric method.
Q. 8 (a) What are liquid crystals? Give their uses in daily life.
(b) Write down the types of solids. Describe the properties of ionic and molecular solids.
Q. 9 (a) Explain Millikan's oil drop experiment to determine the charge on an electron.
(b) Give the postulates of Bohr's atomic model. Also writes the defects in this model.
Q. 10 (a) Derive the equation for the radius of nth orbit of hydrogen atom using Bohr's atomic model.
(b) What are quantum numbers? Briefly describe their types.
Q. 11 (a) Define electron affinity. How is it changed in periodic table? What factors are responsible for its variation?
(b) Write down the main postulates of VSEPR theory and explain the structure of ammonia on the basis of this theory.
Q. 12 (a) Define hybridization process and explain the bonding and structure of methane, ethene and ethyne.
(b) Describe the important points of molecular orbital theory (MOT). Explain the para-magnetic nature of O2 according to this theory.
Q. 13 (a) State first law of thermodynamics. How does it explain (i) qv = ∆E (ii) qp = ∆H.
(b) Define enthalpy of a reaction. How is it measured with glass calorimeter?
Q. 14 (a) State and explain Hess's law of constant heat summation with an example.
(b) State and explain Le-Chatelier's principle.
Q. 15 (a) What is common ion effect? Give its applications.
(b) Write a note on synthesis of ammonia gas by Haber's process, keeping in mind the application of chemical equilibrium in industry.
Q. 16 (a) State different forms of Raoult's law. How this law can help us to understand the ideality of a solution?
(b) Give graphical explanation for elevation of boiling point of a solution. Describe one method to determine the boiling point elevation of a solution.
Q. 17 (a) Balance the following equations by oxidation number method.
(i) Zn + HNO3 → Zn(NO3)2 + NO + H2O
(ii) MnO2 + HCl → MnCl2 + H2O + Cl2
(b) Describe the construction and working of standard hydrogen electrode. (SHE)
Q. 18. (a) What is order of reaction? Describe two methods for finding order of reaction.
(b) What is Arrhenius equation? How can it be used to calculate the energy of a reaction?
Q. 19. Solve the following numerical problems.
(i) Calculate the number of grams of Al2S3 which can be prepared by the reaction of 20 g of Al and 30 g of sulphur. How much the non-limiting is in excess?
(ii) A mixture of two liquids, hydrazine N2H4 and N2O4 are used as a fuel in rockets. They produce N2 and water vapours. How many grams of N2 gas will be formed by reacting 100 g of N2H4 and 200 g of N2O4? (2N2H4 + N2HO4 → 3N2 + 4H2O)
(iii) The combustion analysis of an organic compound shows it to contain 65.44% carbon, 5.50% hydrogen and 29.06% oxygen. What is the empirical formula of the compound? If the molecular mass of this compound it 110.5/mole. Calculate the molecular formula of the compound.
(iv) A well known ideal gas is enclosed in a container having volume 500 cm³ at S.T.P. Its mass comes out to be 0.72 g. What is the molar mass of this gas?
(v) Mg metal reacts with HCl to give H2 gas. What is the minimum volume of HCl solution (27% by mass) required to produce 12.1 g of H2? The density of HCl solution is 1.14 g/cm³.
Mg(s) + 2HCl(aq) → MgCl2(aq) + H2(g)
(vi) NH3 gas can be prepared by heating together two solids, NH4Cl and Ca(OH)2. If a mixture containing 100 g of each solid is heated then calculate the number of grams of NH3 produced.
2NH4Cl(s) + Ca(OH)2(s) → CaCl2(s) + 2NH3(g) + 2H2O(l)
(vii) What pressure is exerted by a mixture of 2.00 g of H2 and 8.00 g of N2 at 273k in a 10 dm³ vessel?
(viii) Calculate the mass of 1dm³ of NH3 gas at 30⁰C and 1000mm Hg pressure, considering that NH₃ is behaving ideally.
(ix) 250cm³ of the sample of hydrogen effuses four times as rapidly as 250cm³ of an unknown gas. Calculate the molar mass of unknown gas.
(x) One mole of methane gas is maintained at 300k. Its volume is 250cm³. Calculate the pressure exerted by the gas when the gas is non-ideal.
a = 2.253atm dm⁶ mole⃜ ² b = 0.0428dm³ mole⃜ ¹
Q. 20. Solve the following numerical problems.
(i) When 2.00 moles of H2 and 1.00 mole of O2 at 100⁰C and 1 torr pressure to produce 2.00 moles of gaseous water, 484.5 kJ of energy are evolved. What are the values of (a) ∆H (b) ∆E for the production of one mole of H2O(g)?
(ii) Neutralization of 100 cm³ of 0.5M NaOH at 25⁰C with 100 cm³ of 0.5M HCl at 25⁰C raised the temperature of the reaction mixture to 28.5⁰C. Find the enthalpy of neutralization. Specific heat of water is 4.2 J/K/g.
(iii) 10.16 g of graphite is burnt in a bomb calorimeter and the temperature rise recorded is 3.8K. Calculate the enthalpy of combustion of graphite, if the heat capacity of the calorimeter (bomb, water, etc) is 86.02 kJ/K.
(iv) Benzoic acid C6H5COOH is a weak mono-basic acid Ka = 6.4 x 10⃜ ⁵ mole/dm³. What is the PH of the buffer containing 7.2 g of sodium benzoate and 0.02 mole benzoic acid?
(v) The solubility of CaF2 in water at 25⁰C is found to be 2.05 x 10⃜ ⁴ mole/dm³. What is the value of Ksp at this temperature?
(vi) N2(g) and H2(g) combine to give NH3(g). The value of Kc in this reaction at 500⁰C is 6.0 x 10⃜ ². Calculate the value of Kp for this reaction.
(vii) What is the percentage ionization of acetic acid in a solution in which 0.1 mole of it has been dissolved per dm³ of the solution?
(viii) Calculate PH of a buffer solution in which 0.11 molar CH3COONa and 0.09 molar acetic acid solutions are present. Ka for CH3COOH is 1.85 x 10⃜ ⁵.
(ix) The solubility of PbF2 at 25⁰C is 0.64 dm⃜ ³. Calculate Ksp of PbF2.
(x) Ca(OH)2 is sparingly soluble compound. Its solubility constant is 6.5 x 10⃜ ⁶. Calculate the solubility of Ca(OH)2.
(b) State Dalton's law of partial pressure. Also give its applications.
Q. 5 (a) State and explain Graham's law of diffusion of gases.
(b) Give postulates of kinetic molecular theory of gases (KMT).
Q. 6. (a) How volume and pressure are corrected by Van der Waal's equation?
(b) What is plasma? How is it formed? Explain its various types.
Q. 7 (a) Define hydrogen bonding. Explain hydrogen bonding in NH3, H2O and HF, how is it helpful in explaining the structure of ice?
(b) What is vapour pressure of a liquid? Describe measurement of vapour pressure by manometric method.
Q. 8 (a) What are liquid crystals? Give their uses in daily life.
(b) Write down the types of solids. Describe the properties of ionic and molecular solids.
Q. 9 (a) Explain Millikan's oil drop experiment to determine the charge on an electron.
(b) Give the postulates of Bohr's atomic model. Also writes the defects in this model.
Q. 10 (a) Derive the equation for the radius of nth orbit of hydrogen atom using Bohr's atomic model.
(b) What are quantum numbers? Briefly describe their types.
Q. 11 (a) Define electron affinity. How is it changed in periodic table? What factors are responsible for its variation?
(b) Write down the main postulates of VSEPR theory and explain the structure of ammonia on the basis of this theory.
Q. 12 (a) Define hybridization process and explain the bonding and structure of methane, ethene and ethyne.
(b) Describe the important points of molecular orbital theory (MOT). Explain the para-magnetic nature of O2 according to this theory.
Q. 13 (a) State first law of thermodynamics. How does it explain (i) qv = ∆E (ii) qp = ∆H.
(b) Define enthalpy of a reaction. How is it measured with glass calorimeter?
Q. 14 (a) State and explain Hess's law of constant heat summation with an example.
(b) State and explain Le-Chatelier's principle.
Q. 15 (a) What is common ion effect? Give its applications.
(b) Write a note on synthesis of ammonia gas by Haber's process, keeping in mind the application of chemical equilibrium in industry.
Q. 16 (a) State different forms of Raoult's law. How this law can help us to understand the ideality of a solution?
(b) Give graphical explanation for elevation of boiling point of a solution. Describe one method to determine the boiling point elevation of a solution.
Q. 17 (a) Balance the following equations by oxidation number method.
(i) Zn + HNO3 → Zn(NO3)2 + NO + H2O
(ii) MnO2 + HCl → MnCl2 + H2O + Cl2
(b) Describe the construction and working of standard hydrogen electrode. (SHE)
Q. 18. (a) What is order of reaction? Describe two methods for finding order of reaction.
(b) What is Arrhenius equation? How can it be used to calculate the energy of a reaction?
Q. 19. Solve the following numerical problems.
(i) Calculate the number of grams of Al2S3 which can be prepared by the reaction of 20 g of Al and 30 g of sulphur. How much the non-limiting is in excess?
(ii) A mixture of two liquids, hydrazine N2H4 and N2O4 are used as a fuel in rockets. They produce N2 and water vapours. How many grams of N2 gas will be formed by reacting 100 g of N2H4 and 200 g of N2O4? (2N2H4 + N2HO4 → 3N2 + 4H2O)
(iii) The combustion analysis of an organic compound shows it to contain 65.44% carbon, 5.50% hydrogen and 29.06% oxygen. What is the empirical formula of the compound? If the molecular mass of this compound it 110.5/mole. Calculate the molecular formula of the compound.
(iv) A well known ideal gas is enclosed in a container having volume 500 cm³ at S.T.P. Its mass comes out to be 0.72 g. What is the molar mass of this gas?
(v) Mg metal reacts with HCl to give H2 gas. What is the minimum volume of HCl solution (27% by mass) required to produce 12.1 g of H2? The density of HCl solution is 1.14 g/cm³.
Mg(s) + 2HCl(aq) → MgCl2(aq) + H2(g)
(vi) NH3 gas can be prepared by heating together two solids, NH4Cl and Ca(OH)2. If a mixture containing 100 g of each solid is heated then calculate the number of grams of NH3 produced.
2NH4Cl(s) + Ca(OH)2(s) → CaCl2(s) + 2NH3(g) + 2H2O(l)
(vii) What pressure is exerted by a mixture of 2.00 g of H2 and 8.00 g of N2 at 273k in a 10 dm³ vessel?
(viii) Calculate the mass of 1dm³ of NH3 gas at 30⁰C and 1000mm Hg pressure, considering that NH₃ is behaving ideally.
(ix) 250cm³ of the sample of hydrogen effuses four times as rapidly as 250cm³ of an unknown gas. Calculate the molar mass of unknown gas.
(x) One mole of methane gas is maintained at 300k. Its volume is 250cm³. Calculate the pressure exerted by the gas when the gas is non-ideal.
a = 2.253atm dm⁶ mole⃜ ² b = 0.0428dm³ mole⃜ ¹
Q. 20. Solve the following numerical problems.
(i) When 2.00 moles of H2 and 1.00 mole of O2 at 100⁰C and 1 torr pressure to produce 2.00 moles of gaseous water, 484.5 kJ of energy are evolved. What are the values of (a) ∆H (b) ∆E for the production of one mole of H2O(g)?
(ii) Neutralization of 100 cm³ of 0.5M NaOH at 25⁰C with 100 cm³ of 0.5M HCl at 25⁰C raised the temperature of the reaction mixture to 28.5⁰C. Find the enthalpy of neutralization. Specific heat of water is 4.2 J/K/g.
(iii) 10.16 g of graphite is burnt in a bomb calorimeter and the temperature rise recorded is 3.8K. Calculate the enthalpy of combustion of graphite, if the heat capacity of the calorimeter (bomb, water, etc) is 86.02 kJ/K.
(iv) Benzoic acid C6H5COOH is a weak mono-basic acid Ka = 6.4 x 10⃜ ⁵ mole/dm³. What is the PH of the buffer containing 7.2 g of sodium benzoate and 0.02 mole benzoic acid?
(v) The solubility of CaF2 in water at 25⁰C is found to be 2.05 x 10⃜ ⁴ mole/dm³. What is the value of Ksp at this temperature?
(vi) N2(g) and H2(g) combine to give NH3(g). The value of Kc in this reaction at 500⁰C is 6.0 x 10⃜ ². Calculate the value of Kp for this reaction.
(vii) What is the percentage ionization of acetic acid in a solution in which 0.1 mole of it has been dissolved per dm³ of the solution?
(viii) Calculate PH of a buffer solution in which 0.11 molar CH3COONa and 0.09 molar acetic acid solutions are present. Ka for CH3COOH is 1.85 x 10⃜ ⁵.
(ix) The solubility of PbF2 at 25⁰C is 0.64 dm⃜ ³. Calculate Ksp of PbF2.
(x) Ca(OH)2 is sparingly soluble compound. Its solubility constant is 6.5 x 10⃜ ⁶. Calculate the solubility of Ca(OH)2.
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