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प्रश्न
True or false
New substances are formed in a chemical change.
पर्याय
True
False
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उत्तर
True
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संबंधित प्रश्न
Define precipitation reaction.
Fill in the blank:
The basic conditions necessary for a chemical reaction is _______
Write true or false :
Hydrogen sulphide has rotten egg smell .
Out of sodium and sulphur which is a metal? Explain its reaction with the oxygen.
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)
Chlorine (Cl2) molecule is formed by ______ of electrons between two chlorine atoms.
Choose the correct option from the bracket and explain the statement giving a reason.
(Oxidation, displacement, electrolysis, reduction, zinc, copper, double displacement, decomposition)
Addition of an aqueous solution of ZnSO4 to an aqueous solution of BaCl2 is an example of ______ reaction.
Give an example of a reaction where the following are involved
Catalyst
Give reason for the following:
Blue solution of copper sulphate changes to green when a piece of iron is added to this solution.
Multiple choice:
A reaction of a type: AB + CD → AD + CD, involves
Write your observation and a balanced equation in the case of the following substances being heated.
Copper carbonate.
Select the correct answer for the following options:
The basic gas obtained when two gases react in presence of a catalyst and the reaction is exothermic.
Give a word equation for the following reaction.
An exothermic reaction where both the reactants are gases, one of which is oxygen.
Give reason for the following:
Even though rusting is an exothermic reaction, the heat evolved when an iron nail rusts is unnoticeable.
On heating which of the following substances i.e. copper carbonate, zinc carbonate, washing soda, copper sulphate, zinc nitrate, copper nitrate, lead nitrate, ammonium chloride and ammonium dichromate – relate to the reaction given below.
A coloured substance which leaves on strong heating a black residue and evolves two colourless gases one of which is acidic and the other neutral.
Complete the table given below.
| Heat on iodine crystals | Colour of vapours evolved |
Complete the table given below.
| Addition of dil. H2SO4 to zinc | Test for gas evolved |
Name the solid residual product formed reaction and state its colour during – thermal decomposition of the following substance.
Copper nitrate.
______ change results in the change of the substance.
Water boiling into water vapour is an example of chemical change.
______ are substances that speed up the process of a chemical change and it will not undergo any change during the course of the reaction.
