Chemistry Class 9th Allied School Malakwal (Part 1) Subjective Total Marks 96 Q1: Give short answers to any TEN of the followings: 1. Define industrial chemistry and analytical chemistry? 2. Differentiate between compound and mixture? 3. Differentiate between homogeneous and heterogeneous mixture? 4. Define atomic mass unit. Why is it needed? 5. What is relative atomic mass and how is it related to gram? 6. Define free radicals and give examples. 7. Find the number of moles in 9.0g of coal (carbon)? 8. State any two defects in the Rutherford atomic model. 9. Write down two postulates of Bohr’s atomic theory. 10. How are positive rays produced in the discharge tube? 11. Who discovered electrons and protons? 12. Define electronic configuration and also give an example? 13. Why do the isotopes of an element have different atomic masses? 14. For what purpose U-325 is used?Also write names of two elements which are produced in U-235 fission reaction? 15. A Patient has a goiter.How will it be detected? 16. What is the importance of oxygen, water and carbon dioxide for life? Q2: Give short answers to any TEN of the followings: 1. Write any two features of a long form of periodic table? 2. What is the trend of atomic radius in period and group? 3. Why are lanthanides and actinides placed separately below the periodic table? Explain. 4. Define shielding effect? Describe its trend in a group and in a period. 5. Give the trend of ionization energy in a period and a group. 6. Define electron affinity with an example. 7. How can an atom accommodate 8 electrons in its valence shell? 8. What is the sign of stability of an atom? 9. Point out the type of covalent bond in the molecules CH4, C2H4, H2, N2, and O2. 10. Draw the Lewis structure diagram of Cl2? 11. Why do you mean by Delta sign and why it develops? 12. What is the difference between malleable and ductile? 13. What are Synthetic adhesives? 14. Write two properties of covalent and coordinate covalent compounds? 15. Define pressure. Write down its unit. 16. Define vapour pressure. Why is it higher at high temperatures? Q3: Give short answers to any TEN of the followings: 1. Define Boyle’s law and write down its mathematical expression? 2. In which form sulphur exists at 100°C? 3. Why are liquids mobile? 4. 5. 6. 7. 8. Give two examples of gas in liquid solution? Define supersaturated solution. How can they be prepared? Why is naphthalene soluble in carbon tetrachloride and not in water? Write any two differences between solution, suspension and colloid. Define oxidation in terms of loss and gain of oxygen and hydrogen. Also give an example. 9. Why are metals called reducing agents and why non metal act as oxidizing agent? 10. Write two differences between electrolytic cell and galvanic cell? 11. What is the difference between spontaneous reaction and non spontaneous reaction? 12. Does aluminium rust? explain. 13. Why is steel plated with nickel before the electroplating of chromium? 14. Write down any two chemical properties of metal, alkali metals and alkaline earth metals? 15. Which group of metals is highly reactive and why? 16. Write the unit of purity of gold? What do you mean by 24 and 22 carat gold? (Part 2) Attempt any 4 questions: (36) 1) Describe the chemical reaction of sodium with water, oxygen, chlorine and hydrogen?(5) Calculate oxidation number of sulphur in H2SO4 and Na2SO4? (4) 2) Define electrolysis and explain the electrolysis of water in detail. (5) If we add 5 cm3 of acetone in water to prepare 90 cm3 of aqueous solution. Calculate the concentration of this solution by % v/v. (4) 3) Define boiling point and explain those factors on which boiling point of liquid depends. (5) What is dipole dipole interaction explained with an example of HCL.(4) 4) Describe the important features of the modern periodic table?(4) The number of CO2 molecules in a pot are 3.01x 1023 .Calculate its moles and mass. (5) 5) How did neutrons discover their properties and also write differences between Rutherford and atomic theory?(5) How many moles are present in 80 grams of phosphoric acid?(4) 6) Define corrosion and write four methods which are used to prevent metal from corrosion? (5) A sample of oxygen gas has a volume of 250cm3 at -30°C. If gas is allowed to expand up to 700 cm3 at constant pressure,find out its final temperature.(4)
