CBSE Questions for Class 7 Chemistry Physical And Chemical Changes Quiz 7 - MCQExams.com

Physical changes are:
  • those in which new substance is not formed.
  • those in which a new substance is formed.
  • always irreversible.
  • None of the above
State true or false.

Evaporation of water is a physical change. 
  • True
  • False
The chemical formula of rust is?
  • $$Fe_{2}O_{3}$$
  • $$Fe$$
  • $$FeO$$
  • $$FeSO_{4}$$
Crystallisation is a:
  • chemical change
  • physical change
  • irreversible change
  • All the above
Identify the chemical change in the following :
  • Freezing of water
  • Rusting of iron
  • Melting of wax
  • Glowing of a bulb
In which type of change , we observed alteration only in specific property of matter but not composition ?
  • chemical change
  • physical change operator
  • Both physical and chemical change
  • None of the above
Baking of dough into bread is a kind of change:
  • That can be reversed
  • That cannot be reversed
  • That can be reversed at every temperature
  • Can't say
Spoiling of food is _______ change.
  • Chemical
  • Physical
  • Reversible 
  • Irreversible 
In a pressure-kerosene stove,
(i) We pump kerosene and convert it into vapours.
(ii) The vapours are then ignited.
Which of the following is true about the above statements?
  • (i) is a chemical change; (ii) is a physical change.
  • (i) is a physical change; (ii) is a chemical change.
  • Both (i) and (ii) are physical changes.
  • Both (i) and (ii) are chemical changes.
Chemical change involves:
  • No change in weight of the reacting substance and the product formed.
  • Change in the composition.
  • Absorption (or) the release of energy.
  • Formation of precipitate.
Identify the chemical changes in the list:
(i) Ripening of fruits
(ii) Fermentation of grapes
(iii) Magnetization of iron
  • Only (i) and (ii)
  • Only (ii) and (iii)
  • Only (i) and (iii)
  • (i), (ii) and (iii)
State whether the following statements are true or false.

Condensation of steam is not a chemical change.
  • True
  • False
Digestion of food is which type of change?
  • Chemical
  • Physical
  • Irreversible
  • Reversible 
Why is zinc better than tin if we want to protect a piece of iron from rusting by electroplating?
  • Zinc is cheaper than tin.
  • Tin is toxic.
  • Rusting is prevented even when the zinc layer is broken.
  • None of these

Which of the following is a chemical change?
  • Burning of coal
  • Dissolving sugar in water
  • Dissolving salt in water
  • Melting of ice
Which of the following statements is true? 
  • Setting of milk to form curd is a chemical and reversible change.
  • Spoiling of food is a chemical and irreversible change.
  • Burning paper is a physical and reversible change.
  • Boiling of an egg is a physical and reversible change.
Rust is a mixture of
  • $$FeO$$ and $$Fe(OH)_3$$
  • $$FeO$$ and $$Fe_3O_4$$
  • $$Fe_2O_3$$ and $$Fe(OH)_3$$
  • $$Fe(OH)_3$$ and $$Fe_3O_4$$
Magnesium hydroxide $${Mg(OH) }_{ 2 }$$ is used as:
  • fermenting agent
  • flavouring agent
  • antacid
  • none of the above
Rust is a hydrated oxide of iron which is 
  • Reddish brown
  • Green
  • White
  • Black
Out of the following processes, which is/are chemical change(s)?
  • Cooking gas starts burning on ignition
  • Iron article undergoes rusting.
  • Erosion of rocks takes place to form soil.
  • Effervescense is formed on adding baking soda into a test tube containing dilute acid.
To prevent rusting, the underside of the ships is coated with:
  • nitric acid
  • phosphoric
  • oxygen
  • red lead oxide paint
Which of these is a physical change?
  • Melting of wax
  • Fermentation
  • Formation of salt solution
  • Boiling of an egg
The process of retting in jute is
  • Microbilological
  • Purely chemical
  • Purely physical
  • Bio-chemical
Match column I with column II and select the correct option from the codes given below.
Column IColumn II
(P) Expansion of metals on heating(i) Neither physical nor chemical change
(Q) A stone kept in the sunlight(ii) Chemical change
(R) Burning of a candle(iii) Combination of physical nor chemical changes
(S) Curdling of milk(iv) Physical change
  • (P) - (iv), (Q) - (i), (R) - (iii), (S) - (ii)
  • (P) - (iv), (Q) - (iii), (R) - (ii), (S) - (i)
  • (P) - (i), (Q) - (ii), (R) - (iii), (S) - (iv)
  • (P) - (i), (Q) - (iv), (R) - (ii), (S) - (iii)
The process in which substances undergo change to produce new substances with new properties are-
  • Chemical changes
  • Physical reactions
  • It is depend on condition
  • None of the above
Write 'True' or 'False' in front of following statements.
The rust formed on the surface of iron easily crumbles.
  • True
  • False
Why are doors painted in our house?
  • To protect them from sun rays
  • To make them dust proof
  • To prevent them rusting
  • To protect them from birds
An example of chemical change is:
  • switching on of bulb
  • milky change of lime water
  • water changes into water vapour
  • melting of ghee
An example of physical change is:
  • rusting
  • melting of ice
  • formation of curd
  • browning of apple after cutting
The piece of alum becomes bigger when another piece of alum is suspended in its solution. This process is known as:
  • Ionisation
  • Transformation
  • Crystallisation
  • Polymorphism
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