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प्रश्न
Fill in the blank.
Melting of ice is a _______ change.
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उत्तर
Melting of ice is a physical change.
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संबंधित प्रश्न
Define precipitation reaction.
Differentiate between in Chemical reaction and chemical equation.
Fill in the blank:
The substances which undergo chemical change are called _______
Balancing a chemical equation is based on
Match the pairs.
| a. | Photosynthesis | i. | Tendency to lose electrons |
| b. | Water | ii. | Reactant in combustion process |
| c. | Sodium chloride | iii. | Chemical change |
| d. | Dissolution of salt in water | iv. | Covalent bond |
| e. | Carbon | v. | Ionic bond |
| f. | Fluorine | vi. | Physical change |
| g. | Magnesium | vii. | Tendency to form anion |
Give an example of the following chemical change.
Two gases combine to form white solid
What do you observe? When
Water is added to the quick lime.
What do you observe when Cl2 is passed through potassium iodide (KI) solution.
Give balanced equation for the following conversion affected by heat alone on the substance:
Ammonium dichromate to nitrogen
Give balanced equation for the following conversion affected by heat alone on the substance:
Zinc nitrate to nitrogen dioxide
Select the correct answer from the options given below:
State the gaseous product formed, when
An active metal reacts with dilute sulphuric acid.
Differentiate between the following:
Neutralization reaction and a precipitation reaction.
________ is a chemical substance which alters the speed of a chemical reaction.
Analogy:
H2O: Water:: NaCl: ______.
Arrange the following statements in correct sequence:
- One side is water-loving and other water-hating molecules.
- When you agitate the cloth, the dirt is surrounded by many molecules and taken away from the cloth.
- The dirt surrounded by the detergent molecules floats in the water making it dirty.
- Finally, the cloth is clean.
- The detergent molecules have two sides.
- Water hating goes and joins with dirt and oil in the cloth while the water-loving joins with the water molecules.
Classify each of the following, as a physical or a chemical change. Give reasons.
(a) Drying of a shirt in the sun.
(b) Rising of hot air over a radiator.
(c) Burning of kerosene in a lantern.
(d) Change the colour of black tea by adding lemon juice to it.
(e) Churning of milk cream to get butter.
Give an example of a chemical reaction for the following situation:
A change in colour is observed
Explain how the painting of an iron gate prevents it from rusting.
Chemical changes are important in our day-to-day life. Give examples.
______ is a chemical substance is used in whitewashing.
