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Class VIIT Chapter 4 - Materials Metals and Non - Metals Science, , Question 1:, , Which of the follawing can be beaten into thin sheets?, (8) Zine (b} Phosphorus (¢) Sulphur (d) Oxygen, Answer;, , {a) Zine, , Question 2;, , Which of the following statements is correct?, , (a) All metals are ductile., , (b) All non-metals are ductile., , {c) Generally, metals are ductile,, , (d) Some non-metals are ductile., , Answer:, , (¢) Generally, metals are ductile, , However, mercury metal— a liquid at room temperature — cannot be drawn into, wires and is not ductile., , Question 3:, , Fill in the blanks:, , (a) Phosphorus is a very___ non-metal., , (b) Metals are conductors of heat and, , {c) Iron is___ reactive than copper., , {¢) Metals react with acids to produce______— gas., Answer:, , (8) Phosphorus is a very __reactive _ non-metal., , (b) Metals are __good conductors of heat and __electricity _., {c) Iron is__more__ reactive than copper,, , (d) Metals react with acids to produce __hydrogen gas., Question 4:, , Mark ‘T’ if the statement is true and ‘F’ if it is false., , (a) Generally, nan-metals react with acids. ( ), , (b) Sodium is a very reactive metal, ( ), , , , Page 1 of 6

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Class VIIT Chapter 4 - Materials Metals and Non - Metals Science, , (c) Copper displaces zinc from zinc sulphate solution. { ), {¢) Coal can be drawn into wires. { ), Answer:, {i} Generally, non-metals react with acids, (F), (ii) Sodium is a very reactive metal. (T), (il) Copper displaces zinc from zinc sulphate solution. (F), {iv) Coal can be drawn into wires. (F), Question 5:, Some properties are listed in the following Table, Distinguish between metals and, non-metats on the basis of these properties., , , , Properties Metals | Non-metals, , , , 1. Appearance, , 2. Hardness, , 3. Malleability, , 4. Ductility, , 5. Heat Conduction, , 6, Conduction of Electricity, , , , , , , , , , , , , , , , Answer:, , Properties Metals Non-metals, , 1. Appearance Lustrous: Dull, , 2. Hardness: Hard Soft, , 3. Malleability Can be beaten into thin] Cannot be beaten into thin, , 4. Ductility sheets sheets, , 5. Heat conduction Can be drawn into wires ‘Cannot be drawn into wires, , 6. Conduction — of | Good conductors of heat Poor conductors of heat, , electricity Good conductors — of | Poor conductors of electricity, electricity, , , , , , , , , , , , Page 2 of 6

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Glass VIIT Chapter 4 - Materials Metals and Non - Metals Science, , Question 6:, , Give reasons for the following., , (8) Aluminium foils are used to wrap food items., , {b) Immersion rods for heating liquids are made up of metallic substances., , (c) Copper cannot displace zinc from its salt solution., , {d) Sodium and potassium are stored in kerosene,, , Answer:, , {a) Aluminium foils are used to wrap food items because aluminium metal is, malleable, Therefore, it can be beaten into thin foils,, , (b) Metals are good conductors of heat and electricity. Therefore, immersion rods for, heating liquids are made of metallic substances., , {c) A metal can displace a less reactive metal from its salt in an aqueous solution., But zinc is more reactive than copper. Therefore, copper cannot displace zinc from its, salt solution,, , Cus) + ZNSOs ao) = NO reaction, , {d) Sodium and potassium are stored in kerosene because they are highly reactive, elements. They can easily catch fire even when in contact with air., , Question 7:, , ‘Can you store lemon pickle in an aluminium utensil? Explain., , Answer:, , Lemon pickle cannot be stored in aluminium utensils because lemon pickle contains, acids, which can react with aluminium (metal) liberating hydrogen gas. This can lead, to the spoiling of the pickle., , Question 8:, , Match the substances given in Column A with their uses given in Column B., , , , , , , , , , A 8B, (i) | Gold (a) | Thermometers, (ii) | fron (b) | Electric wire, , , , , , , , , , , , , , Page 3 of 6

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Glass VIIT, , Chapter 4 - Materials Metals and Non - Metals, , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , (iii) | Aluminium | (c) | Wrapping food, (iv) | Carbon (d) | Jewellery, , {v) | Copper (e) | Machinery, , (vi) | Mercury (f) | Fuel, , Answer:, , A B, , (i) | Gola (d) | Jewellery, , (ii) | Tron (e) | Machinery, , (iii) | Aluminium | (c) | Wrapping food, {iv) | Carbon (f) | Fuel, , {v) | Copper (b) | Electric wire, (vi) | Mercury | (a) | Thermometers, Question 9:, , What happens when, , (a) Dilute sulphuric acid is poured on & copper plate?, () Iron nails are pleced in copper sulphate solution?, Write word equations of the reactions involved., , Answer:, {a) When dilute sulphuric acid is poured on a copper plate, the copper metal reacts, , with sulphuric acid to liberate hydrogen gas., Copper (Cu) + Sulphuric acid (H SO, 1 —> Copper sulphate (CuSO_) + Hydrogen was |H_), , Science, , , , Page 4 of 6

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Class VIIT Chapter 4 - Materials Metals and Non - Metals Science, , (D) Iron being more reactive displaces copper from copper sulphate solution. In this, reaction, the dlue colour of copper sulphate fades and there is deposition of copper, ‘on the iron neil,, , Iron (Fe) + Copper sulphate (CuSO,) — Iron sulphate (FeSO_) + Copper (Cu), , Question 10:, , Saloni took a piece of burning charcoal and collected the gas evolved in a test tube., {a) How will she find the nature of the gas?, , {®) Write Gown word equations of all the reactions taking place in this process., Answer:, , (a) Add a few drops of water in the test tube containing gas. Now, cover the test, tube and shake it well, After shaking, test the solution with blue litmus and red, litmus. It will turn blue litmus red. Thus, the gas is acidic in nature,, , (b) Charcoal reacts with oxygen to form carbon dioxide gas., , c + OO, — > CO,t, Carbon, from (Oxygen) (Carbon dioxide), charcoal |, , Carbon dioxide reacts with water to form carbonic acid, which turns blue litmus, paper red., , co, + Ho — > Ho,, {Carbon dioxide) (Water) (Carbonic acid), , (Tums blue litmus red), , Question 11:, One day Reeta went to a jeweller’s shop with her mother. Her mother gave an old, gold jewellery to the goldsmith to polish. Next day when they brought the jewellery, back, they found that there was a slight loss in its weight. Can you suggest a reason, for the loss in weight?, , , , Page 5 of 6