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प्रश्न
A physical change is temporary. Explain.
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उत्तर
A physical change is defined as a change in which no new substance is formed.
A physical change is temporary because this change can be easily reversed by reversing the conditions. For example when ice is melted, it gets converted into water by absorbing heat. Water so formed can be easily converted to ice by cooling thus heat is released. Thus physical change is temporary.
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संबंधित प्रश्न
Write short answer.
Give two examples of periodic changes
State whether the following is physical or chemical changes.
cutting wood into small pieces —
What is a chemical change ? Give two examples of chemical changes.
State which of the following pertain to – chemical changes.
- Substance retains its identity.
- The change is permanent.
- No new substance is formed.
- Is easily reversible.
- Produces one or more new substances by a change in its composition.
- The change is temporary.
- The composition and properties of the original substance are not altered.
Select the chemical changes from the following list of changes
Boiling of milk.
Gas exists in three states as solid, liquid, and gas.
Match the items of Column I with the items of Column II.
| Column I | Column II | ||
| (a) | Large crystals | (i) | Turns lime water into milky |
| (b) | Depositing a layer of zinc on iron | (ii) | Physical change |
| (c) | Souring of milk | (iii) | Rust |
| (d) | Carbon dioxide | (iv) | Sugar candy (Mishri) |
| (e) | Iron oxide | (v) | Chemical change |
| (f) | Dissolving common salt in water | (vi) | Galvanisation |
A physical change is generally____________.
Cutting a log of wood into pieces is a chemical change.
Mention some of the different conditions needed for chemical changes to occur.
