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No chemical reaction takes place when granules of a solid A, are mixed with the powder of another solid B
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1
|
1115
|
March 29, 2019
|
|
(a) What is meant by corrosion? Name any two methods used for the prevention of corrosion
|
|
1
|
4863
|
March 29, 2019
|
|
(a) What is a reactivity series? Describe an activity to develop a reactivity series
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1
|
2191
|
March 29, 2019
|
|
(a) What are ionic compounds? List any four physical properties of these compounds
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1
|
2332
|
March 29, 2019
|
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Give reasons for the following: (i) Metals are regarded as electro-positive elements
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1
|
2915
|
March 29, 2019
|
|
How is an alloy made? List two proposes of making alloys and mention the constituents and two properties of each of the following alloys:
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1
|
1367
|
March 29, 2019
|
|
Give reasons for the following observations: (i) Ionic compounds in general have high melting and boiling points
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1
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7179
|
March 29, 2019
|
|
1. What is an alloy? How does it differ from an amalgam?
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1
|
1462
|
March 29, 2019
|
|
What is meant by ‘rusting’? With labelled diagrams describe an activity to find out the conditions under which iron rusts
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1
|
12986
|
March 29, 2019
|
|
(i) Arrange the following metals in decreasing order of their reactivity: Fe, Zn, Na, Cu, Ag
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1
|
2050
|
March 29, 2019
|
|
(a) Name a metal for each case: (i) It does not react with cold as well as hot water but reacts with steam
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1
|
7115
|
March 29, 2019
|
|
Give reasons for the following: (a) Metals can be given different shapes according to our needs
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1
|
8168
|
March 29, 2019
|
|
Give reasons for the following: (a) Gold and silver are used to make jewellery
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1
|
3320
|
March 29, 2019
|
|
What are amphoteric oxides? Choose the amphoteric oxides from amongst the following oxides:
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1
|
16301
|
March 29, 2019
|
|
Explain the following terms by giving one exafhple of each:
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|
1
|
625
|
March 29, 2019
|
|
Give reasons for the following: (i) Metals are regarded as electro-positive elements
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|
1
|
937
|
March 29, 2019
|
|
Explain the Froth Flotation?
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|
1
|
655
|
March 29, 2019
|
|
(a) What would you observe when you put: (i) Some zinc pieces into blue copper sulphate solution?
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1
|
16082
|
March 29, 2019
|
|
Give reasons for the following: (a) Na, K and Ca metals form hydride by combination with hydrogen gas, but most other metals do not
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|
1
|
4548
|
March 29, 2019
|
|
Give reasons for the following: (a) Zinc oxide is considered as an amphoteric oxide
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|
1
|
18102
|
March 29, 2019
|
|
Write chemical equations for reactions taking place when:
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|
1
|
2070
|
March 29, 2019
|
|
Give reason for the following: (a) Silicon counts among metalloids
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|
1
|
2733
|
March 29, 2019
|
|
(i) How are metalloids different from metals? Name a metalloid
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|
1
|
1601
|
March 29, 2019
|
|
Write chemical equations for the reactions taking place when: (i) Zinc sulphide is heated in air
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|
1
|
1446
|
March 29, 2019
|
|
Give reasons for the following: (i) Metals conduct electricity
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|
1
|
1942
|
March 29, 2019
|
|
(a) What are strategic metals? Give one example also. (b) State the reason for the following behaviour of zinc metal:
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|
1
|
2150
|
March 29, 2019
|
|
Curd is not kept in copper and brass utensils. Why?
|
|
1
|
2869
|
March 29, 2019
|
|
(a) Distinguish between ionic and covalent compounds in the following properties:
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|
1
|
824
|
March 29, 2019
|
|
Name the metals which reacts violently with cold water. Write any three observations
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|
1
|
800
|
March 29, 2019
|
|
Choose the metal (from the list given below) which can displace zinc from zinc sulphate solution
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|
1
|
2805
|
March 29, 2019
|