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प्रश्न
Define catalyst.
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उत्तर
A catalyst is a substance that either increases or decreases the rate of a chemical reaction without itself undergoing any chemical change during the reaction.
संबंधित प्रश्न
Name three biochemical catalysts found in the human body.
FILL IN THE BLANK
In a ............ change, new substances are formed.
True or false
New substances are formed in a chemical change.
Copper carbonate when heated, it turns :
Explain the following reaction with one suitable example of Decomposition reaction
Choose the correct option from the bracket and explain the statement giving reason.
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Explain by writing a word equation.
Limestone powder disappears on adding to dilute hydrochloric acids.
What do you observe when Cobalt chloride paper is introduced in water vapour.
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NH3 and SO2
Write your observation and a balanced equation in the case of the following substances being heated.
Copper nitrate.
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.
Give a balanced equation for a reaction involving the evolution of gas on the addition of dilute acid to calcium carbonate.
Select the correct answer from the options given below:
State the gaseous product formed, when
An ammonium salt reacts with an alkali.
What kind of a change is associated with decaying of a plants?
Chemical change is a temporary change.
______ change results in the change of the substance.
Galvanization is a process in which ______ is coated as a layer of iron.
Give an example where heat, light, and sound are produced during a chemical change.
Write a note on the following:
Fermentation
