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ICSE Class X Prelims 2020 : Chemistry (Don Bosco School, Park Circus, Kolkata)

4 pages, 15 questions, 10 questions with responses, 10 total responses,

Rakshak Awasthi
Don Bosco School, Park Circus, Kolkata

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SHARADA MANDIR SCHOOL STD : 10 FIRST TERM EXAM AUG 2017 Marks: 80 Time: 2Hrs CHEMISTRY Instructions: 1. The first 15 minutes is to be spent on reading the question paper. 2. The time given on the head of the paper is the time allowed for writing the answers. 3. Section A is compulsory. Attempt any four questions from section B 4.The intended marks for questions or parts of questions are given in brackets. 5. Section B is to be started on a fresh side of the supplement. 6. Copy the grid given for the Q. No and marks given in the beginning of Section B Section A (Attempt all questions) Question 1 A] Fill in the blanks. [Write only the answers] [5] 1) The gas given off at cathode during the electrolysis of acidulated water is _______.(oxygen , hydrogen) 2) Calcium salts with sodium hydroxide to give _______ coloured precipitate. (brick red, white) 3) The number of atoms present in one molecule of an element is called its ________. (atomicity, atomic number) 4) A non-metal in group 17, which is liquid is _________. (mercury, bromine) 5) A term that represents how many times an atom of an element is heavier than th mass of carbon atom. (atomic weight, molecular weight) C] Give one word/ Phrase for the following. 1) Homologous series of hydrocarbons with general formula CnH2n. 2) A chloride which gives reddish brown precipitate with sodium hydroxide solution. 3) The largest atom in the third period. 4) Impurities which remain behind at the bottom of the cell during electrorefining. 5) Solution obtained by dissolving sulphur trioxide in 98% sulphuric acid. [5] D] Draw the structural formula for the following compounds. 1) 4 methyl pentan 1 ol 2) 2, 2 dimethyl butane [2] E) The following questions are about electroplating a copper wire with silver. 1) What ions must be necessarily present in the electrolyte? 2) Of what substance must the anode be made up of? 3) What will be the cathode made up of? [3] F. 1] Write balanced chemical equations for the following reactions. a) A mixture of acetylene and hydrogen is passed over nickel at 300oC. b) Zinc metal is heated with dilute sulphuric acid. [2] 2] Complete the following equations and balance. a) CaC2 + H2O [3] Te st Pa p er z. co m B] Choose the correct answer from the options given below. [5] 1) The functional group present in acetic acid is: a) ketone b) alcohol c) aldehyde d) carboxylic acid 2) A gas which has an offensive smell like rotten eggs. a) oxygen b) hydrogen c) hydrogen sulphide d) ammonia 3) On moving from left to right across a period of the periodic table, the non-metallic character of the elements: a) decreases b) increases c) remains the same d) depends on the period 4) The vapour density of carbon dioxide [C= 12, O= 16] is : a) 12 b) 16 c) 44 d) 22 5) The number of C H bonds in ethane molecule are: a) four b) six c) eight d) ten b) C2H5OH + CH3COOH c) C2H5OH + Na Cont d.... 1 www.testpaperz.com Page 2 CHEMISTRY Std 10 G] Compound A is amorphous in nature. On heating it evolves a gas 'B' which turns lime water milky which confirms the presence of anion C and residue D . When NH4OH is added to sample it forms insoluble white precipitate which confirms the presence of cation E . Identify A, B, C, D and E. [5] H] CO2 + C 2CO [ C=12, O=16] 1) What mass of carbon will be utilized to reduce 112ml of carbon dioxide at STP? 2) What volume of CO will be formed in this reduction? [5] I] 1) The compound A has the following percentage composition by mass: [C= 12, O= 16, H=1] carbon= 26.7%, oxygen=71.1%, hydrogen= 2.2%. Determine the empirical formula of A. 2) If the relative molecular mass of A is 90, what is molecular formula of A? [5] SECTION B (Attempt any FOUR questions) Question No. Marks obtained Question 2 A] State your observation. 1) Sugar is heated with concentrated sulphuric acid. 2) Manganese dioxide is treated with concentrated hydrochloric acid. 3) Ammonium hydroxide is added to iron (II) sulphate solution. 4) Ammonia gas is passed through Nessler s reagent. z. co m [4] Pa p er B] A, B, C are three elements in which B is an inert gas having Z=10. With this information complete the following table. [Draw the table] [6] Element Atomic number No. of electrons in the valence shell A Z 1 B Z C Z+1 Also, explain the following: a) Electron affinity of element A is more than that of element C. b) Ionization energy of element C is less than that of element A. c) Electron affinity of B is zero. [2] Te st Question 3 A] Write the correct IUPAC name for each of the compounds whose structural formulae are given below. 1] 2] B] Study the given figure and answer the question that follows. [4] 1) Why silica crucible is used in this type of electrolysis? 2) What is observed at the anode after electrolysis? 3) Write the equations of the reaction which take place at the cathode and anode. Cont d.... 2 www.testpaperz.com Page 3 CHEMISTRY Std 10 C] Calculate the number of : 1) moles present in 90 g of H2O. 2) molecules in 5000 ml of nitrogen dioxide. [N=14, O=16, H=1] [4] Question 4 A] Name the following. 1) A hydrocarbon used for cutting and welding. 2) A catalyst used in Contact process. 3) An organic compound used as a thermometric liquid. [3] B] Classify the following substances into strong electrolytes, weak electrolytes and non electrolytes. 1) Potassium chloride 2) lead acetate 3) Carbon tetra chloride 4) Ammonium hydroxide. [2] C] Following questions are based on the electrolysis of aqueous copper sulphate using copper electrodes. [3] 1) Write the reactions taking place at anode and cathode. 2) State one appropriate observation for the above electrolysis. z. co m D] Calculate the percentage by weight of water of crystallization in magnesium sulphate crystals, MgSO 4. 7 H2O [Given atomic masses: Mg= 24, S=32, O=16, H=1] [2] Question 5 A] Write the structural formula of the following functional groups. 1) Ketone 2) Ether [2] [4] C] Write one chemical test with observation to confirm the presence of the following ions/radical. 1) Potassium 2) Sulphite [4] Pa p er B] State the property of sulphuric acid displayed in the following statements. 1) Sulphuric acid can form two kinds of salts with sodium chloride. 2) When carbon is heated with concentrated sulphuric acid, carbon dioxide is formed. 3) Concentrated sulphuric acid must be stored in airtight bottles to prevent dilution. 4) When concentrated sulphuric acid is added to crystalline copper sulphate, it turns powdery white. Question 6 A] Match the type of reactions with the following reactions. Column A Column B 1) Methane from sodium ethanoate a) Halogenation 2) Monochloromethane from methane b) Dehydrohalogenation 3) Ethene from bromoethane c) Substitution d) Decarboxylation 4) 1, 2 dichloro ethene from Ethyne Te st [4] B] Copy and complete the following table which refers to the action of heat on some carbonates. Carbonate Colour of residue on cooling 1) Zinc carbonate 2) Lead (II) carbonate [2] C] Study the table below and answer the following questions carefully. Elements A B Mass number 23 20 Number of neutrons 12 10 1) To which groups do A, B and C belong? 2) To which periods do A, B and C belong? 3) Which amongst A, B and C is (a) an alkali metal (b) halogen? [4] C 35 18 Cont d.... 3 www.testpaperz.com Page 4 CHEMISTRY Question 7 A] What is glacial acetic acid? Std 10 [1] B] The usefulness of a fertilizer depends upon percentage of nitrogen present in it. Find which of the following is a better fertilizer: [N=14, H=1, O=16, P=31] [3] 1) Ammonium nitrate [NH4NO3] 2) Ammonium phosphate [(NH4)3PO4] [2] D] With reference to electroplating give a reason for each of the following. 1) Articles are electroplated. 2) A small current is passed for a longer period is preferred over high current for a shorter period. [2] E] Define isomerism. Give the IUPAC name of the isomer C 4H10 which has a branched chain. [2] z. co m C] In a laboratory how will you distinguish between Ca(NO3)2 and NaNO3? Te st Pa p er ********* End ********* 4 www.testpaperz.com

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