Very Short Question Answers - Physical and Chemical Changes Class 7 Notes | EduRev

Science Class 7

Class 7 : Very Short Question Answers - Physical and Chemical Changes Class 7 Notes | EduRev

The document Very Short Question Answers - Physical and Chemical Changes Class 7 Notes | EduRev is a part of the Class 7 Course Science Class 7.
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Very Short Q & A :


Q1: What is rust?

Ans : When iron oxide is hydrated, it is known as Rust(Fe2O3. XH2O)


Q2: What type of change in rust?

Ans : Chemical change


Q3: What type of change is photosynthesis?

Ans : Chemical change


Q4: What is a chemical change?

Ans : A change, in which a new substance with different properties is formed, is known as a chemical change.


Q5: A change, in which a new substance with different properties is formed, is known as a _________________.

Ans : Chemical change


Q6: ___________is a property by virtue of which a metal can be beaten into thin sheets without breaking.

Ans : Malleability


Q7: Write the chemical formula of blue vitriol.

Ans : Crystals of copper sulphate pent hydrate (CuSO4.5H2O) are blue in colour. So, it is commonly known as blue vitriol.


Q8: State the two important conditions for rusting.

Ans : Presence of water and presence of oxygen


Q9: What is freezing point of water?

Ans : The freezing point is 0°C at which water freezes.


Q10: What is freezing of water?

Ans : Freezing is the process in which water turns to ice when cold enough (below 0°C temperature).


Q11: What is melting?

Ans : Melting is the process of turning a solid to a liquid.


Q12: Name the process by which water molecules continuously change to vapour.

Ans : Evaporation


Q13: At what temperature water evaporates?

Ans : 100 °C


Q14: In physical change a new substance is formed. (True/False).

Ans : False


Q15: The jumping of a person from some height is a chemical change.(True/False)

Ans : False


Q16: Extraction of metal is a chemical process or physical process?

Ans : Chemical process


Q17: A medicine is the end product of the chain of ________________________.

Ans : Chemical reaction


Q18: Sound may be produced during a chemical reaction yes or no?

Ans : Yes


Q19: During a chemical reaction

Ans : All of these


Q20: Heat, light or any other radiation like UV rays may be given off or absorbed during a physical change (True/False).

Ans : False


Q21: Iron pipes coated with zinc do not get rusted easily. (True/False).

Ans : True


Q22: Condensation of steam is chemical process or physical change?

Ans : physical change


Q23: Cutting of log of wood into pieces is a chemical process or physical change?

Ans : physical change


Q24: Name the two methods by which rusting of iron can be prevented.

Ans : By painting or greasing and by galvanizing with chromium or zinc


Q25: Setting of curd is a _______________ process.

Ans : Chemical


Q26: Give an example of chemical change in which heat, light, sound and unpleasant gases are produced.

Ans : Explosion of a firework


Q27: Digestion is a __________________ change.

Ans : Chemical


Q28: Spoiling of food is a ____________________ change.

Ans : Chemical


Q29: Which of the two is permanent change chemical change or physical change?

Ans : Chemical change


Q30: Define galvanisation.

Ans : The process of depositing a layer of zinc on iron is called galvanisation.


Q31: Name the metals involved in making stainless steel.

Ans : Chromium, nickel and manganese.


Q32: What kind of change involved in burning of coal?

Ans : Chemical change


Q33: Formation of manure from leave is a physical change. (True/False)

Ans : False


Q34: Write down the equation representing the process of rusting.

Ans : 

Iron(Fe) + oxygen (O2)->water (H2O) + rust (iron oxide Fe2O3)


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