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प्रश्न
What is a chemical reaction?
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उत्तर
“Chemical reaction is a chemical change in which matter changes into a new substance or substances.”
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संबंधित प्रश्न
The gas we use in the kitchen is called liquefied petroleum gas (LPG). In the cylinder, it exists as a liquid. When it comes out from the cylinder it becomes a gas (Change − A), then it burns (Change − B). The following statements pertain to these changes. Choose the correct one.
Complete and balance the following chemical equations:
`"H"_2"S"` + `"CI"_2` `→`
Complete and balance the following chemical equations:
Zn + `"H"_2"SO"_4` `→`
(dil)
What are oxides ?
FILL IN THE BLANK
In a ............ change, new substances are formed.
TRUE \ FALSE
Positively charged electrode is called the anode. True or false ?
How is precipitate formation in a chemical reaction indicated?
Name the type of chemical reaction shown by the following equation:
Fe + CuSO4 → FeSO4 + Cu
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)
Electron ______ is complete in each hydrogen in a hydrogen molecule.
Explain,giving one example of the following chemical changes:
Reversible reaction
Multiple choice:
A reaction of a type: AB + CD → AD + CD, involves
Name affects the acidified K2Cr2O7 paper and also turns lime water dirty milky.
Complete the following table and write your observations.
|
Hydrogen sulphide |
Ammonia |
Sulphur dioxide |
Hydrogen chloride |
|
|
Shake the gas with red litmus solution |
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Shake the gas with blue litmus solution |
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Apply a burning splint to a gas |
Write your observation and a balanced equation in the case of the following substances being heated.
Copper nitrate.
Write your observation and a balanced equation in the case of the following substances being heated.
Ammonium chloride
The changes in which new substance with new chemical properties are formed are ______.
Silver articles turning black: ______:: Boiling of H2O: physical 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.
Match the following:
| Column I | Column II | ||
| 1. | Burning of coal | a. | Rusting |
| 2. | Painting of a surface | b. | Evaporation |
| 3. | Dipping iron in the water | c. | Chemical change |
| 4. | Salt from seawater | d. | Prevention of rusting |
______ is the chemical name of limestone.
