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प्रश्न
Define chemical reaction.
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उत्तर
Any chemical change in matter that involves its transformation into one or more new substances is called a chemical reaction.
संबंधित प्रश्न
Give one example that illustrates the following characteristics of a chemical reaction:
Change in state
Write true or false :
No new substance is formed during a chemical reaction.
Name the type of chemical reaction shown by the following equation:
CaCO3 → CaO + CO2
Complete the statement by filling the gap using an 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)
An ______ is drawn in between the reactants and products while writing the equation for a chemical reaction.
Give an example of the following chemical change.
Two solids combine to form a liquid
Write the chemical reaction where the following changes are observed.
Physical state is changed
Multiple choice:
Which of the following is not a characteristic of a chemical change?
What do you observe? When
Water is added to the quick lime.
Write your observation and a balanced equation in the case of the following substances being heated.
Ammonium chloride
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.
A salt which reacts with ammonium hydroxide to give a reddish brown precipitate.
A chemical reaction is often accompanied by external indications or characteristics which include –
- Colour change
- Effervescence or gas evolved
- Evolution or absorption of heat
- Formation of a precipitate.
With reference to each of the above indications, state the external indication seen during – Thermal decomposition of mercury [II] oxide.
When an aqueous solution of potassium chloride is added to an aqueous solution of silver nitrate, a white precipitate is formed. Give the chemical equation of this reaction.
Rusting of Iron: undesirable change:: Dead plants turn into manure: ______.
The percentage composition of Nitrogen in Ureas is ______.
State whether the following statement is true or false:
When a candle burns, both physical and chemical changes take place.
Galvanization is a process in which ______ is coated as a layer of iron.
Iron and rust are the same substances.
When milk is mixed with coffee decoction, the colour of milk and decoction changes due to ______.
Acid rain is a result of ______.
