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Jeevaj
Subject: Science
, asked on 14/3/18
If the reaction between zinc oxide and sodium Hydroxide produces na2zn(oh)4 hpw is it an amphioteric oxide
Answer
3
Payal Arora
Subject: Science
, asked on 14/3/18
Q. explain the observations of this experiment
⚫
Take an aluminium or copper wire. Clamp this wire on a stand, as shown in Fig. 3.1.
⚫
Fix a pin to the free end of the wire using wax.
⚫
Heat the wire with a spirit lamp, candle or a burner near the place where it is clamped.
⚫
What do you observe after some time?
⚫
Note your observations. Does the metal wire melt?
Answer
2
Prajesh Raghu
Subject: Science
, asked on 13/3/18
Why do metals and none metals react? ILLUSTRATE WITH EXAMPLE
Answer
1
Prajesh Raghu
Subject: Science
, asked on 13/3/18
What are the drawbacks of chemical equation? Illustrate with example
Answer
1
Champ Jee
Subject: Science
, asked on 13/3/18
Q. No reaction takes place when granules of a solid 'A' are mixed with a powder of solid 'B'. However when the mixture is heated a reaction starts with evolution Of much heat. Product 'C' of the reaction settles down as a liquid metal and solid product, 'D' keeps floating over the liquid 'C'. This reaction is sometimes used for making metals for ready use in Odd places.
(i) Based on this information make assumptions about 'A' and 'B' and corresponding deductions about C' and 'D' and write a balanced chemical equation for the reaction. Include in the equation the information about physical states of the reactants and products, need of heating for starting the reaction and the reaction being exothermic.
(ii) Name two types of chemical reactions to which this reaction can belong.
Answer
1
Uday
Subject: Science
, asked on 13/3/18
Plz i have been scoring less in practical questions plss some tipz on that pls
Answer
1
Nishant Kumar
Subject: Science
, asked on 13/3/18
copper does not with hcl . then how 'cu +2hcl=cucl2+h2 . Explain
Answer
3
Shweta Verma
Subject: Science
, asked on 12/3/18
An element X on reacting with oxygen forms an oxide having formula Xo2. The oxide dissolves in water to turn blue litmus red. Identity the element whether it is a metal or non metal.
Answer
3
Shweta Verma
Subject: Science
, asked on 12/3/18
Mention an ore of zinc other than zinc oxide. By which process can this ore be converted into zinc oxide.
Answer
1
Shweta Verma
Subject: Science
, asked on 12/3/18
Silver articles and copper get a black and green coating respectively when kept for longer time.in air. Mention the reason for this and identify the chemical name of coating in each case.
Answer
5
Chirag Khatri
Subject: Science
, asked on 9/3/18
Q 11. (a) Name a metal for each case:
(i) It does not react with cold as well as hot water but reacts with steam.
(ii) It does not react with any physical state of water.
(b) When calcium metal is added to water, the gas evolved does not catch fire but the same gas evolved on adding sodium metal to water catches fire. Why is it so ?
Q 12. Name the system which facilitates communication between central nervous system and the other parts of the body. Mention two types of nerves it consists of along with their organs of origin.
Answer
4
Son Ser
Subject: Science
, asked on 7/3/18
In electrolytic refining of silver why silver nitrate is used as electrolyte and not silver sulphate .???plzzz fast its urgent
Answer
2
Nirlipta Padhy
Subject: Science
, asked on 5/3/18
State the reaction of aluminium with sodium hydroxide solution. Can Al displace Na from its aqueous solution?
Answer
4
Payal Arora
Subject: Science
, asked on 2/3/18
Q.11. You are given samples of three metals - sodium, magnesium and copper. Suggest any two activities to arrange them in order of their decreasing reactivity.
Explain reactivity of metals on the basis of their reaction with water or acid or salt solutions.
Answer
3
Tushar
Subject: Science
, asked on 1/3/18
Hold any of the samples taken above with a pair of tongs and try burning a flame. Repeat with the other metal samples.
Collect the product if formed.
Let the products and the metal surface cool down.
Which metals burn easily?
What flame colour did you observe when the metal burnt?
How does the metal surface appear after burning?
Arrange the metals in the decreasing order of their reactivity towards oxygen.
Are the products soluble in Water?
Answer
2
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What are you looking for?
Take an aluminium or copper wire. Clamp this wire on a stand, as shown in Fig. 3.1.
Fix a pin to the free end of the wire using wax.
Heat the wire with a spirit lamp, candle or a burner near the place where it is clamped.
What do you observe after some time?
Note your observations. Does the metal wire melt?
(i) Based on this information make assumptions about 'A' and 'B' and corresponding deductions about C' and 'D' and write a balanced chemical equation for the reaction. Include in the equation the information about physical states of the reactants and products, need of heating for starting the reaction and the reaction being exothermic.
(ii) Name two types of chemical reactions to which this reaction can belong.
(i) It does not react with cold as well as hot water but reacts with steam.
(ii) It does not react with any physical state of water.
(b) When calcium metal is added to water, the gas evolved does not catch fire but the same gas evolved on adding sodium metal to water catches fire. Why is it so ?
Q 12. Name the system which facilitates communication between central nervous system and the other parts of the body. Mention two types of nerves it consists of along with their organs of origin.
Explain reactivity of metals on the basis of their reaction with water or acid or salt solutions.