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प्रश्न
How do the following help in bringing about a chemical change?
heat.
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उत्तर
Some chemical reactions take place only in the presence of heat.
e.g. When lead nitrate is heated, it breaks into lead monoxide, nitrogen dioxide and oxygen.
\[\ce{\underset{\text{(lead nitrate)}}{2Pb(NO3)2}->[heat]\underset{\text{lead monoxide}}{2PbO} +\underset{\text{nitrogen dioxide}}{4NO2} + O2}\]
APPEARS IN
संबंधित प्रश्न
State whether the following statement is true or false. In case a statement is false, write the corrected statement.
Condensation of steam is not a chemical change.
Define catalyst.
Complete and balance the following chemical equation:
\[\ce{Pb(NO3)2 ->[Heat]}\]
MULTIPLE CHOICE QUESTIONS
Tick the most appropriate answer.
Reduction reaction is the exact opposite of
- displacement reaction
- decomposition reaction
- oxidation reaction
- none of these
Fill in the blank
A new substance is always formed in a _______ change.
Explain the term reactant and product giving examples.
Write the chemical reaction where the following changes are observed.
Colour change is noticed
Multiple choice:
Thermal decomposition of sodium carbonate will produce
What do you observe? When
Sodium chloride solution is added to silver nitrate solution.
Give one example electrochemical reaction.
Give balanced equation for the following conversion affected by heat alone on the substance:
Copper carbonate to copper oxide
Give a balanced equation for the conversion of an ammonium salt to a basic gas.
Give a balanced equation for the conversion of a soluble lead salt to an insoluble lead salt – formed as a white precipitate.
Name the solid residual product formed reaction and state its colour during – thermal decomposition of the following substance.
Zinc carbonate.
________ is a chemical substance which alters the speed of a chemical reaction.
The changes in which new substance with new chemical properties are formed are ______.
Two chemical species X and Y combine together to form a product P which contains both X and Y
\[\ce{X + Y -> P}\]
X and Y cannot be broken down into simpler substances by simple chemical reactions. Which of the following concerning the species X, Y and P are correct?
(i) P is a compound
(ii) X and Y are compounds
(iii) X and Y are elements
(iv) P has a fixed composition
Write the equation for the process of formation of rust.
When carbon dioxide is passed through lime water ______.
The reaction of H2 gas with oxygen gas to form water is an example of ______.
