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सी.आई.एस.सी.ई.आईसीएसई ICSE Class 7

State Four Conditions Necessary for Chemical Reactions to Take Place.

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प्रश्न

State four conditions necessary for chemical reactions to take place.

एक पंक्ति में उत्तर
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उत्तर

Conditions necessary for chemical reactions :

  1. Close contact
  2. Solution form
  3. Heat
  4. Light
  5. Catalyst
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अध्याय 5: Language of Chemistry - Exercise

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सेलिना Concise Chemistry [English] Class 7 ICSE
अध्याय 5 Language of Chemistry
Exercise | Q 2

संबंधित प्रश्न

Changes in which new substances are formed are called ______ changes.


When baking soda is mixed with lemon juice, bubbles are formed with the evolution of a gas. What type of change is it? Explain.


FILL IN THE BLANK

In a double decomposition precipitation reaction both the reactants must be ............ soluble.


Explain the type of reactions on the basis of the direction of reaction.


Write true or false  : 

Hydrogen sulphide has rotten egg smell .


A chemical equation is a statement that describes a chemical change in terms of


Complete the statement by filling the gaps using appropriate term from the terms given in the bracket.

(slow, coloured, arrow, fast, smell, milky, physical, product, chemical, reactant, covalent, ionic, octet, duplet, exchange, sharing, equality sign)

Oxygen is a ______ in respiration.


Show with the help of diagram of electronic configuration how the following compound is formed from the constituent atoms.

Hydrogen chloride


Choose the correct option from the bracket and explain the statement giving reason.
(Oxidation, displacement, electrolysis, reduction, zinc, copper, double displacement, decomposition) 

The conversion of ferrous sulphate to ferric sulphate is ______ reaction. 


What do you observe when H2S is passed through a lead nitrate solution.


Distinguish by dilute sulphuric acid.

Sodium sulphide and sodium sulphite?


Give a word equation for the following reaction.

A compound which on heating shows – colour change from brown to yellow.


Give a word equation for the following reaction.

An exothermic reaction where both the reactants are gases, one of which is oxygen.


A chemical reaction is often accompanied by external indications or characteristics which include – 

  1. Colour change
  2. Effervescence or gas evolved
  3. Evolution or absorption of heat
  4. Formation of a precipitate.

With reference to each of the above indications, state the external indication seen during – Addition of dilute acid to an active metal.


Give a balanced equation for the conversion of a soluble lead salt to an insoluble lead salt – formed as a white precipitate.


______ change results in the change of the substance.


On heating calcium carbonate gets converted into calcium oxide and carbon dioxide.

(a) Is this a physical or a chemical change?

(b) Can you prepare one acidic and one basic solution by using the products formed in the above process? If so, write the chemical equation involved.


Write the equation for the process of formation of rust.


Write five changes in the characteristics of a substance that can take place during a chemical change. 


Write the characteristics of chemical change.


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