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GOLDCREST HIGH, LATUR 2nd TERM END EXAMINATION (2018-19) GRADE: 9 SUBJECT: SCIENCE PAPER-2 (CHEMISTRY) Time: 2 Hours Max. Marks: 80 Answer to this question must be written on the paper provided separately. You will not be allowed to write answers for the first 15 minutes. This time is to be spent on reading the question paper. The time given at the head of this paper is the time allotted for the writing the answer. The paper is divided into two sections. Attempt all questions from Section A and any four questions from Section B. The intended marks for questions or parts of questions are given in brackets [ ] SECTION-I (40 Marks) (Attempt all questions from this Section) Question-1 (a) Write the balanced Chemical equation for the following reactions: [5] (i)Silver oxide + hydrogen peroxide Silver + water +oxygen. (ii)Aluminium + sodium hydroxide +water sodium aluminate + hydrogen. (iii)Iron + hydrochloric acid Iron(II) chloride +hydrogen. (iv)Potassium bicarbonate + Sulphuric acid Potassium sulphate +carbon dioxide + water. (v) Potassium Hydroxide + Nitric acid Potassium Nitrate + water. (b) Fill in the blanks from the words A to F below. A: Decreases B: Increases C: Remains same [5] D: Increase by one E: Electropositive F: Electronegative (i)Across a period from left to right in the modern periodic table: No. of electron shells_____; No. of valence electrons______; Electronegativity_______; Character of elements changes from _______to______. (ii)Down a group in the modern periodic table: No. of electron shells_____; No. of valence electrons______; Electronegativity_______; Character of elements changes from _______ to ______. (c) Give appropriate scientific reason for the following statements: (i) Alkali metals are good reducing agents. [5] (ii) The mass number of an atom is slightly less than the actual atomic mass. (iii) Why Nitric acid and hot concentrated sulphuric acid not used in the preparation of hydrogen? (iv)Why Caesium is the most metallic element and Flourine is the most non-metallic element? (v) Hydrogen is collected by the downward displacement of water and not of air, even though it is lighter than air. TEE-2/CHE/2018-19/KSH This question paper consists of 5 printed pages and 1 blank page Page 1 (d) The electronic configuration of an element T is 2, 8, 7. (i)What is the group number of T ? (ii)What is the period number of T? (iii)How many valence electrons are there in an atom of T? (iv)What is the valency of T? (v) Is it a metal or non-metal? [5] (e) State the correct salt from the list-II which on thermal decomposition exhibits the change in colour from the list-I 1 to 5 [5] 1. 2. 3. 4. 5. List-I Light green to black White to yellow Blue to black Orange to green Blue to white List-II A. Copper carbonate B. Hydrated copper sulphate C. Copper nitrate D. Ammonium dichromate E. Zinc nitrate (f) State the following with reference to the extract from the following Periodic Table. [5] (i)The valency of elements in Group IVA,VA. (ii)A covalent bond formed between an element in Period 2 and a halogen. (iii)An electrovalent compound formed between an alkaline earth metal and a halogen. (iv)The bridge element of Period 3 of Group IA , IIA and IIIA. (v)The typical elements of Period 2 and 3 of group IVA and VA. (g) Identify P.Q.R.S.T in each case based on the information given below: (i) A gas P turns moist starch iodide paper blue black (ii) A gas Q turns moist red litmus blue (iii) A gas R turns Affects acidified K2Cr2O7 and turns lime water dirty milky (iv) A gas S turns responsible for bleaching action (v) A gas T turns blue cobalt chloride paper light pink (h) Why are the following metals not used in the laboratory preparation of hydrogen? (i) Lead (ii) Calcium (iii) Iron (iv) Aluminium (v) Sodium TEE-2/CHE/2018-19/KSH This question paper consists of 5 printed pages and 1 blank page [5] [5] Page 2 SECTION-II (40 MARKS) (Attempt any four questions from this section) Question-2 (a) Atoms of elements X, Y and Z have 16, 17 and 19 electrons, respectively. Atoms of argon have 18 electrons. Determine the formulae of the compounds formed by the combination of the atoms of the elements: (i) X and Z (ii) Y and Z (iii) X with itself. [2] (b) The table above describes some particles. (i) Which three particles are neutral atoms? (ii) Which particle is a negative ion? What is the charge on this ion? (iii) Which particle is a positive ion? What is the charge on this ion? (iv)Which two particles are isotopes? [2] (c) Aluminium and nitrogen react to form an ionic compound called aluminium nitride. These show the electron arrangement for the two elements: Answer these questions for an aluminium atom. (i) Does it gain or lose electrons, to form an ion? (ii) How many electrons are transferred? (iii) Is the ion formed positive, or negative? (iv) What charge does the ion have? (v) Give the electron distribution for the ions formed by the two atoms. (vi)What do you notice about these distributions? Explain it. (vii)Name another non-metal that will form an ionic compound with aluminium, in the same way as nitrogen does. [6] Question-3 (a) Chlorine is an element with atomic number 17.It is a mixture of two isotopes having mass number 35 and 37.With this respect (i) Draw the electron dot and cross diagram of CaCl2 (ii) What is meant by atomic number of an element ? (iii) What would be the reason for an element to have atoms with different mass numbers? (iv) Give one property of hydrogen chloride which agrees with it being a covalent compound. (v) Give one property of magnesium chloride which agrees with it being an ionic compound [5] TEE-2/CHE/2018-19/KSH This question paper consists of 5 printed pages and 1 blank page Page 3 (b)Give the equation for the following conversions A1 to A5 ZnSO4 ZnCO3 Zn(NO3)2 [5] Zn(OH)2 ZnO Zn Question-4 [5] (a)Complete the following equation in chemical formula and then write down the balanced equation in each: (i)Zinc nitrate + Sodium Carbonate .. + (ii)Ferrous sulphate + Sodium Hydroxide + .. (iii) Silver Nitrate + Hydrochloric acid(dil) + .. (iv) Potassium Nitrate + Sulphuric acid(dil) + (v) Lead (II) oxide + Sulfur dioxide .. + (b) Give balanced equations for the liberation of hydrogen using water as the reactant with [3] (i) an active metal (ii) a trivalent metal (iii) a metal that undergoes a reversible reaction with water. (c) Give the general group characteristics applied to hydrogen with respect to similarity in properties of hydrogen with: (i) alkali metals of group 1 (ii) halogens of group 17. With special reference to valency electrons and ion formation [2] Question-5 (a) Electrolysis of acidulated water a produces gas. With this respect fill the table below: S.NO NAME OF THE ELECTROLYTE 1 H2O (acidified) NAME OF CATHODE Platinum foil NAME OF ANODE Platinum foil REACTION AT CATHODE [2] REACTION AT ANODE (b) Complete the following [3] Haber s Process: N2 + H2 _?__ . Temp_____?______, Pressure____?____, Catalyst____?___, Promoter__?____, Type of reaction _?__ (c) Complete and balance the following Chemical Equations: (i)Zinc with Dilute Sulphuric acid give zinc sulphate and hydrogen gas (ii)Cupric oxide with Dilute Sulphuric acid form cupric sulphate and water. (iii)Cupric oxide with ammonia form copper , nitrogen gas and water. (iv)Thermal decomposition of nitric acid give nitrogen dioxide, water and oxygen (v)Thermal decomposition of Sodium nitrate give sodium nitrite and oxygen gas. TEE-2/CHE/2018-19/KSH This question paper consists of 5 printed pages and 1 blank page [5] Page 4 Question-6 (a) Arrange the following elements as directed: (i) Li, K, Na (increasing order of electron shells) (ii) F , N , O (increasing order of atomic size) (iii) Li ,O, C, F (increasing order of tendency to form cations) (iv) Ar, He, Ne (decreasing order of number of electron shells) (v) Na , C, N, F (decreasing order of tendency to form anions) (b) Give a chemical test to distinguish between the following gases: (i) Carbon dioxide and Sulphur dioxide (ii) Ammonia and hydrogen chloride (iii) Chlorine and nitrogen dioxide (iv) Hydrogen chloride and hydrogen sulphide (v) Chlorine and nitrogen dioxide. [5] [5] Question-7 (a) 12Mg 24 and 12Mg26 are symbols of two isotopes of magnesium. Compare the atoms of these isotopes with respect to: (i) the composition of their nuclei. (ii) their electronic configurations (iii) Give reasons why the two isotopes of magnesium have different mass numbers. [3] (b) Draw the electron dot and cross(Lewis Diagram) of the following: N2, HCl, H2O, NH3, CH4, CCl4 [6] (c) What is the significance of the number of protons found in the atoms of different elements? [1] TEE-2/CHE/2018-19/KSH This question paper consists of 5 printed pages and 1 blank page Page 5
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