Name: Physical and Chemical Changes Explained
Uploaded: 2019-07-19
Duration: 5 min 35 s
Description: Millions of changes happen around us. These changes can be physical changes or chemical changes. Do you know the difference between them? Learn how to distin...

Question

Solve the crossword puzzle.

ACROSS

1. Substances that undergo chemical reactions

4. Reaction between acids and bases are called

5. Reaction of silver nitrate and potassium iodide is an example of this type of reaction

6. heat is absorbed in this type of reaction

DOWN

2. The technique used to obtain pure substances from the solution

3. This type of change is usually permanent and irreversible

Accepted Answer

Across:

1. Reactants are the substances that undergo chemical reaction. They are the starting materials used in the reaction.

Across:

4. Reaction between acids and bases are called neutralisation reactions. Salt and water are the products formed in this reaction.

Across:

5. Reaction of silver nitrate and potassium iodide is an example of precipitation reaction. Silver iodide formed in this reaction is insoluble in water and it remains as precipitate.

6. Heat is absorbed in endothermic reaction. During such reactions the surrounding of reaction becomes cool.

Down:

2. The technique used to obtain pure substances from the solution is crystallisation. That is, pure substance is obtained in the form of shiny crystals and impurities are removed with the filtrate.

Down:

3. Chemical change is usually permanent and irreversible. Burning of paper is an example for this.

Process	Physical change	Chemical change
Evaporation of perfume on your skin
Burning of sugar
Melting of copper metal
Tearing a piece of aluminium foil
Fermentation
Condensation
Sublimation

Important Questions on Chemical Changes and Reactions

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