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VIBGYOR HIGH First Term Examination AY 2020-2021 CHEMISTRY SCIENCE PAPER-2 Grade: IX Max. Marks: 80 Date: 18/09/2020 Time Allowed: 2 hours INSTRUCTIONS: Section A is compulsory. Attempt any four questions from Section B The intended marks for the questions or parts of questions are given in brackets [ ] This question paper contains 8 printed pages. _________________________________________________________________________ [40] Section I (40 marks) Attempt all questions from this section Q. 1 (a) Fill in the blanks with the choices given in brackets: i. [5] _________is the chemical formula of green vitriol. [FeSO4.7H2O / Ca (NO3)2.4H2O] ii. At 0 K the volume of a gas is theoretically _________. [0 cc,273 cc] iii. The radicals of zinc carbonate are _________ and ________. [ Zn2+ and CO3-2/ Zn1+ and CO3-1}. iv. With the rise in temperature the solubility of sodium chloride in water_________. [increases sharply/increases only a little] v. (b) 1 cm3 of a gas is equal to _________. [1000 ml l /1 ml] Choose the most appropriate answer for each of the following: i. The formula of ferric sulphate is A. FeSO4 1 [5] B. Fe2SO4 C. Fe3SO4 D. Fe2(SO4)3 ii. The salt whose solubility in water decreases with rise in temperature. A. Calcium sulphate B. Sodium nitrate C. Potassium nitrate D. Ammonium chloride iii. The valency of Mg in Mg3N2 is A. +1 B. -1 C. +2 D. +3 iv. A hygroscopic substance formed from a divalent metal. A. MgCl2 B. CaO C. KOH D. FeCl3 v. The volume of a given mass of a gas at 270C is 50 cc. To what temperature should it be heated at the same pressure so that it will occupy a volume of 75 cc? A. 187.50C B. 1650C 2 C. 1770C D. 145.80C (c) Select from the list that matches the description given in each case: [5] [Fluorine, Magnesium, Silicon, Copper, Oxygen (d) (e) (f) i. A metalloid in period 3 of the periodic table. ii. A gas produced by the action of light on hydrogen peroxide. iii. A metal which does not react with dilute acids. iv. A non-metal that belongs to group 17 of the periodic table. v. An atom of an element which contains 2 electrons in M shell. Match the atomic number 2,9,20,11 and 14 with each of the following: i. The most reactive halogen. ii. A non-metal of valency 4. iii. An element with zero valency. iv. An alkaline earth metal in period 4. v. A metal with one electron in the third shell. Write a balanced chemical equation for each of the following: i. Action of steam on Calcium hydride. ii. Formation of sulphuric acid from Sulphur trioxide. iii. Action of concentrated sodium hydroxide solution on aluminium. iv. Action of carbon dioxide on Magnesium oxide. v. Reduction of Sulphur using hydrogen. State one relevant observation for each of the following reactions: i. On heating hydrated copper sulphate. ii. Ferric chloride reacts with sodium hydroxide. 3 [5] [5] [5] iii. On heating ammonium dichromate. iv. Thermal decomposition of ammonium chloride. v. (g) Reaction of zinc with sulphuric acid. Match Column A with Column B: [5] Ans: Column A (h) Column B i. Univalent metal a. Chlorine ii. Gaseous oxidizing agent b. Neon iii. Univalent non-metal c. Potassium iv. Inert gas d. Bromine v. Liquid non-metal. e. F2 i. Calculate A) Molecular [3] mass of urea [NH2CONH2] and ammonium sulphate[(NH4)2SO4] B) Percentage of Sulphur in ammonium sulphate [(NH4)2SO4] [Atomic mass of N=14, O=16, H=1, C=12, S=32] ii. Find the percentage of nitrogen in KNO3. [2] [Atomic mass of K=39, N=14, O=16] Section II (40 marks) [40] Attempt any four questions from this Section Q. 2 [10] (a) Answer the questions in short: i. [3] Mention 2 methods by which a saturated solution can be converted to an unsaturated solution. ii. State Boyle s Law 4 iii. (b) How does temperature affect the solubility of gases in water? In the laboratory preparation of hydrogen. i. [3] Write the balanced chemical equation for the laboratory preparation of hydrogen. ii. How is hydrogen collected? iii. Name the reagents used in the above process to remove moisture from the gas collected. (c) Classify the following reactions as Direct combination, [4] Decomposition, Displacement, Precipitation and Neutralization. i. Mg + 2HCl ii. (NH4)2Cr2O7 iii. CO2 +H2O iv. 2NaCl +Pb(NO3)2 MgCl2 +H2 Cr2O3 +4H2O +N2 H2CO3 2 NaNO3 +PbCl2 Q. 3 [10] (a) Draw atomic orbit structure for the formation of the following Compounds: 5 [6] i. Calcium oxide ii. Nitrogen molecule iii. (b) Distinguish between the following: i. (c) Water [2] Copper sulphate and Ferrous sulphate (by using sodium hydroxide). Write balanced chemical equation for the following: i. Production of water gas using steam. ii. Reduction of steam to hydrogen by carbon monoxide. Q. 4 [2] [10] (a) Give reason for each of the following i. [3] Volumes of gases are converted into STP conditions and then compared. (b) ii. Common salt becomes sticky and wet during rainy season. iii. Gas exerts pressure in all direction. Fill in the blanks: [3] i. Solubility of gases in water decreases with_________ in pressure. ii. M(OH)2 is a hydroxide of a metal M . _________is the formula of its sulphate. iii. Electronegativity across a period _________from left to right in the modern periodic table. (c) A gas X at a pressure of 750mm of Hg and temperature of 35 oC has a [4] volume of 3.2 litres. Find the volume of the gas X at s.t.p. Q. 5 [10] (a) Differentiate between the following: i. [3] Efflorescence and Deliquescence 6 (b) ii. Atomic number and Mass number iii. Unsaturated and Saturated solution Complete the following table relating to the atomic structure of some [4] elements: Element Atomic Mass Number Number of Number Number Number of Neutrons Aluminium 27 Phosphorus 15 (c) of protons electrons 13 13 15 16 A compound is formed from an atom X [atomic no.=11]and an atom [3] Y [atomic no.=17]. i. Write the electronic configuration of atom Y ii. State the type of bond formed between X and Y. iii. Write the chemical formula of the compound formed between X and Y? Q. 6 [10] (a) Give balanced equations for the following reactions: i. [3] Oxidation of potassium iodide into iodine and potassium hydroxide by using hydrogen peroxide. ii. Reduction of Zinc oxide into Zinc and carbon monoxide by using coke. iii. (b) Reaction of Iron with steam Give the formula of the following compounds: i. Glauber s salt ii. Epsom salt iii. Gypsum 7 [3] (c) Identify the gas evolved in each case: i. [4] The gas evolved when amphoteric metals react with hot concentrated alkali. ii. A colourless, odourless gas that rekindles a burning splinter. iii. A pungent smelling gas evolved when hydrogen reacts with nitrogen. iv. A reddish-brown gas liberated on heating silver nitrate crystals. Q. 7 [10] (a) (b) (c) Name the following: [3] i. Highly reactive univalent metals. ii. Horizontal rows of the periodic table. iii. Elements of group 3 to 12 of the periodic table. Define the following: i. Water of crystallization ii. Relative atomic mass iii. Solubility i. [3] A gas is allowed to expand at a constant temperature from an initial [2] volume of 200ml to a final volume of 1200 ml. At the end of expansion, the pressure of the gas was found to be 2 atmospheres. What was the initial pressure of the gas? ii. State Charles law [1] iii. Convert the following: 1 atm =_____ cm Hg [1] **** * 8
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