Imp XI Past Paper 2024 - PDF

DHACSS DEGREE COLLEGE FOR BOYS & GRILS KHAYABAN-E-RAHAT, PHASE-VI, DHA KARACHI Important Topics Chapter 1 (Stoichiometry) i. What is meant by actual yield? Why it is always less than theoret...

DHACSS DEGREE COLLEGE FOR BOYS & GRILS KHAYABAN-E-RAHAT, PHASE-VI, DHA KARACHI Important Topics Chapter 1 (Stoichiometry) i. What is meant by actual yield? Why it is always less than theoretical yield in a reaction? ii. Define the following terms. a) Mole b) Avogadro’s number c) Limiting Reactant d) Stoichiometry e) Exponential notation iii. What is meant by rounding off the data? Write down the rules of rounding off the data. Numericals i. Aluminium chloride is used in the manufacturing of rubber. It is produced by allowing Aluminium to react with Cl2 gas at 650oC, as shown: 2Al(s) + 3Cl2(g) → 2AlCl3(aq) When 160g Aluminium reacts with excess of chlorine, 650g of AlCl3 is produced. What is the percentage yield of AlCl3? ii. The reaction of calcium carbonate with hydrochloric acid is given as: CaCO3(s) + 2HCl(aq) → CaCl2(aq) + CO2(g) + H2O(l) If 50 grams of CaCO3(s) react with an excess of hydrochloric acid to form 14.52 grams of CO 2(g), calculate the percentage yield of the reaction. iii. Calculate the number of moles and molecules in: (a) 38g of carbon disulphide (b) 68.4g of sucrose (C12H22O11) iv. 1.6g of a sample of gas occupies a volume of 1.12dm3 at STP. Determine the molar mass of the substance. v. Simplify (3.25×104) by using rules of exponential notation. Chapter 2 (Atomic Structure) i. Compare the properties of subatomic particles. ii. Write the postulates of Bohr atomic theory. Derive an expression for radius and energy of nth orbit in hydrogen atom. Also discuss the defects of Bohr’s model of atom. iii. Define radioactivity. Describe the characteristics of alpha, beta and gamma particles. iv. Discuss and compare the types of spectra. Chapter 4 (States of Matter-Gas) i. State the postulates of kinetic molecular theory of gases. ii. State Boyle’s law, Charles’ law and Avogadro’s law and derive an expression for the equation of state for gases. Also calculate the value of general gas constant in different units. iii. State and explain the following laws: (a) Graham’s law of diffusion (b) Dalton’s law iv. Explain Linde’s method of liquefaction of gases. Numericals i. 1.40dm volume of a gas collected at a temperature of 27oC and pressure of 900 torr was found to 3 have a mass 2.273g. Calculate the molecular mass of the gas. ii. Calculate the density of oxygen gas at 45oC and at 1.54 atmospheric pressure. iii. Laughing gas (N2O) at 30oC and 820 torr pressure occupies a volume of 10.32 dm3. Calculate the volume that it will occupy at standard temperature and pressure.  Chapter 5 (States of Matter-Liquids) i. What are the different inter-molecular forces found in liquid molecules? Explain each briefly. ii. Explain anomalous behavior of water due to hydrogen bonding. iii. Define the following a) Molar heat of vaporization b) Molar heat of sublimation c) Molar heat of fusion iv. Give reasons for the following a. A falling drop of liquid is spherical. d. Evaporation is a cooling process b. Mercury has its meniscus upward. e. Liquids cannot be compressed c. Honey is more viscous than water f. Density of water is highest at 4oC Chapter 6 (States of Matter-Solids) i. Differentiate between a) Isomorphism and polymorphism b) Crystalline and amorphous solids ii. What is a unit cell? Sketch a unit cell and label the dimensions a, b, c and α, β and γ. How do cubic and tetragonal cells differ? iii. What are the different types of crystalline solids? Explain each briefly. iv. Define anisotropy. Which type of solids have this property? v. Define Allotropy. Diamond and graphite both are allotropic form of carbon. Graphite conducts electricity while diamond does not? Explain. Chapter 10 (Solutions and colloids) i. What are the different properties of colloidal solutions? ii. Differentiate between colloids and suspension. iii. State Raoult’s law and derive its mathematical expression. iv. What are the colligative properties of solution? Explain Elevation of boiling point and depression of freezing point in detail. Numericals i. Define molarity. Calculate the molarity of a solution if 6.24g NaOH is dissolved in water and the solution is made up to 100cm3 in a volumetric flask. ii. A solution is prepared by mixing 46g ethanol (C2H5OH) and 180g water. Calculate the mole fraction of both components. iii. 4.0mg NaOH is dissolved in 2.5dm3 solution. Find its concentration in ppm. Chapter 11 (Thermochemistry) i. What is meant by Enthalpy change (ΔH)? Under what conditions the change in the internal energy change (ΔE) of a system and ΔH become equal? ii. What are thermochemical reactions? Draw energy diagrams for different types of thermochemical reactions. iii. State and explain the first law of thermodynamics. Derive an expression of pressure-volume work. iv. Define the following terms a. Open system b. Closed system c. Entropy d. Enthalpy v. Define standard enthalpy of formation. vi. What is Born-Haber cycle? Sketch a labeled Born-Haber cycle for the formation of NaCl(s). Numericals i. A thermochemical process is carried out at constant pressure of 8.52atm. If it absorbs 1.4KJ energy from the surrounding due to which an expansion in the volume of 4.7dm3 is occurred. Calculate its  change in internal energy. ii. Glycerol (C3H8O3) is a well-known organic compound due to its versatile uses. Calculate the standard enthalpy of formation of glycerol from the data given below. 3C+ 4H2 +3/2O2 → C3H8O3 ΔHf =? C+ O2 → CO2 ΔH = -393.5KJ/mol 1 H 2 + 2 O 2 → H 2O ΔH = -258.5KJ/mol 1 C3H8O3 +3 2 O2 → 3CO2 + H2O ΔH= -1654.1KJ/mol iii. Draw a fully labelled Born Haber cycle for Rubidium chloride (RbCl) and determine the lattice energy by using the following values. (all in KJ/mol) I.P1st of Rb =403 Electron Affinity of Cl= -394 Bond energy of Cl2= 242 Sublimation energy of Rb= 86.5 Heat of formation of RbCl(s)= -430.5 iv. In the manufacturing of nitric acid by the Ostwald’s method, one of the most important exothermic reactions is the oxidation of ammonia. 4NH3+5O2 → 4NO+ 6H2O Determine standard heat of reaction (∆Ho) from the following given data. ∆Hfo of NH3= -46.19KJ/mol ∆Hfo of NO= 90.25KJ/mol ∆Hfo of H2O=-285.8KJ/mol