Science: Synthetic Fiber and Ans

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  • Topic: Synthetic fiber, Fiber, Plastic
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  • Published : October 24, 2012
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(Q.)Give one example of each: metals and non-metals.
(Ans)  
Metals: Copper.
Non-Metals: Sulphur.

(Q.)Name the metal, which is the best conductor of heat and electricity. (Ans)  
Copper.
(Q.)Name the property by virtue of which metals can be drawn into thin wires. (Ans)  
Ductility.

Q.)Name the gas produced, when metals reacts with acids.
(Ans)  
Hydrogen gas.

(Q.)What is the color of the copper sulphate solution?
(1 Mark)
(Ans)  
Blue.
(Q.)State the nature of oxides of non-metals.
(1 Mark)
(Ans)  
The oxides of non-metals are generally, basic in nature.

(Q.)Which metal is stored in kerosene?
(1 Mark)
(Ans)  
Sodium.
(Q.)Name the property of the metal by which it can be drawn into thin sheets. (1 Mark)
(Ans)  
Malleability.
Q.)What happens when sulphur reacts with oxygen?
(1 Mark)
(Ans)  
Sulphur di oxide is formed.
S + O2 SO2
(Q.)Which non-metal catches fire, if exposed to air?
(1 Mark)
(Ans)  
Phosphorus.
(Q.)Name the gas that burns with a POP sound.
(1 Mark)
(Ans)  
Hydrogen gas.
(Q.)What are displacement reactions?
(1 Mark)
(Ans)  
The reactions in which more reactive metals displace less reactive metals from their compounds in aqueous solution are called displacement reaction.

(Q.)Give one use of non-metal in our daily life.
(1 Mark)
(Ans)  
Chlorine gasis used in purification of water.
(Q.)What are metalloids?
(1 Mark)
(Ans)  
Metalloids are those elements which possess some properties of metals and some properties of non-metals.

(Q.)Which metal is use to wrap food items?
(1 Mark)
(Ans)  
Aluminium.
(Q.)What happens when sulphur di- oxide reacts with water? Give the chemical reaction involved. (2 Marks)
(Ans)  
When sulpur dioxide reacts with water, sulphurous acid is formed. SO2 + H2O H2SO3

(Q.)Why lemon pickle cannot be stored in an aluminium foil? (2 Marks)
(Ans)  
Aluminium reacts with the citric acid present in the lemon. Hence, lemon pickles can't be stored in aluminium vessels. (Q.)Write two important properties of metals.
(2 Marks)
(Ans)  

Properties of metals:
(a) Good conductors of heat and electricity.

(b) Lustrous, i.e., theyhave shiny appearance.
(Q.)Why copper cannot displace zinc from zinc sulphate solution? (2 Marks)
(Ans)  
Copper is less reactive than zinc. Hence, copper cannot displace zinc from zinc sulphate solution.

(Q.)Why immersion rods for heating liquids are made up of metallic substances? (2 Marks)
(Ans)  
Metals are good conductors of heat. Hence, immersion rods for heating liquids are made up of metallic substances.

(Q.)What happens when iron nails are dipped in water in a test tube for a week? (2 Marks)
(Ans)  
When iron nails are dipped in water in a test tube for a week,a brown layer gets deposited on the iron nails, which isknown asrust.

(Q.)What happens when magnesium ribbon is burnt in air?
(2 Marks)
(Ans)  
When metals burn in air, theformation of their oxide takes place. Hence, when Magnesium reacts with air, magnesium oxide is formed. 2Mg+O22MgO

(Q.)In a chemistry experiment, a student by mistake put some magnesium strips in blue coloured copper sulphate solution. What change will he observe in the colour of the solution? Write the reaction also. (2 Marks)

(Ans)  
When magnesium strips are added to the blue coloured copper sulphate solution, the colour of the solution disappears because magnesium is more reactive than copper. It displaces copper from copper sulphate solution. Mg + CuSO4 MgSO4 + Cu

Q.)(a)You must have seen in the laboratory that sodium metal is always stored in kerosene oil. Why is it so? (b)Name a non-metal that is very reactive and is stored in water. (2 Marks)
(Ans)  
(a)Sodium metal is very reactive. It reacts vigorously with air and water and a lot of heat is generated. Therefore, it is kept in kerosene. (b)Phosphorous

(Q.)What happens when iron reacts with oxygen and water? Give the chemical reaction involved. (3...
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