Olympiad – Class VI – Science - Che - Changes around us

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Question - 1

Study the table given below.

Which of the above changes is wrongly classified?

  • A W
  • B X
  • C Y
  • D Z

Question - 2

Why is the rusting of iron termed as a chemical change?

  • A It is a temporary change.
  • B It can be cleaned and the original substance can be recovered.
  • C It is a slow reaction.
  • D A new substance is formed.

Question - 3

Pasteurisation of milk is a

  • A physical and reversible change
  • B chemical and reversible change
  • C chemical and irreversible change
  • D neither physical nor chemical change

Question - 4

Which of the following are desirable changes?
(i) Drying of clothes
(ii) Growth of weeds
(iii) Cement getting hard when exposed to moisture
(iv) Desalination of  sea water

  • A Only (i) and (ii)
  • B Only (ii) and (iii)
  • C Only (i) and (iv)
  • D Only (i), (ii) and (iv)

Question - 5

What is the change taking place in the following processes?

  • A Irreversible, physical change
  • B Chemical change
  • C Reversible, physical change
  • D Reversible, chemical change

Question - 6

Sheela cooked rice in a rice cooker. What kind of change took place?
(i) irreversible change
(ii) Endothermic change
(iii) Natural change

  • A Only (i) and (ii)
  • B Only (ii) and (iii)
  • C Only (i) and (iii)
  • D (i), (ij) and (iii)

Question - 7

Nitrogen reacts with hydrogen under high temperature and pressure and forms ammonia. Which type of change is undergone in the given example?

  • A A chemical change
  • B A physical change
  • C An exothermic reaction
  • D A natural change

Question - 8

Which of the following is NOT a feature of a physical change?

  • A It is reversible.
  • B It is temporary.
  • C No new substance is formed.
  • D The composition of the substance changes.

Question - 9

Choose the incorrect statement.

  • A The heating of sugar is a permanent change.
  • B Sugar decomposes to form charcoal.
  • C The crystallisation of sugar is a chemical change.
  • D The powdering of sugar is a physical change

Question - 10

What kind of change do the batteries used in a wrist watch undergo?

  • A A physical change
  • B A periodic change
  • C A chemical change
  • D An endothermic change