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6th Grade > Chemistry

CHANGES AROUND US MCQs

Total Questions : 97 | Page 1 of 10 pages
Question 1. What happens when sugar is heated? What kind of change is it? [2 MARKS]
 Discuss Question

:
Process : 1 Mark
Identification of the change : 1 Mark
When sugar is continuously heated, a black powdery substance is formed which is called charcoal.
Since a new product is formed, it is considered to be a chemical change.
Question 2. Melting of wax is a/an _________ change , while burning of a candle is a/an _________ change.
  1.    reversible ,  reversible
  2.    reversible , irreversible
  3.    irreversible , reversible
  4.    irreversible , irreversible
 Discuss Question
Answer: Option B. -> reversible , irreversible
:
B
When we burn a candle the melted wax can be solidified. However, the wick of the candle once burnt cannot be regained or reproduced. Hence, the burning of a candle is an irreversible change as we can use the molten wax to make the candle again(after solidifying) however we will require a new wick.
Question 3. Which among the following types of change are being depicted in the below figure?
Which Among The Following Types Of Change Are Being Depicted...
  1.    Irreversible and physical
  2.    Reversible and physical
  3.    Irreversible and chemical
  4.    Reversible and chemical
 Discuss Question
Answer: Option A. -> Irreversible and physical
:
A
Changes which can't be reversed are called irreversible changes.
The change in which the composition of the original substance remains unchanged and no new substance is formed during a change is called physical change.
The figure depicts the cutting of an apple. Cutting of an apple is an irreversible change, as we cannot get the whole apple back in its original shape from the cut apple. It is also a physical change as apple's physical structuregets changed and no new product is formed in the process.
Question 4. The growing of a moustache over a boy's face is a reversible change.
  1.    True
  2.    False
  3.    Statement A is false; Statement B is true
  4.    Both the statements are false
 Discuss Question
Answer: Option A. -> True
:
A
The changes that can be undone are reversible change. Growingof moustache over a boy's face can be undone by shaving it. So it isa reversible change.
Question 5. Following figure shows change.
Following Figure Shows  Change.
  1.    reversible
  2.    irreversible
  3.    periodic
  4.    permanent
 Discuss Question
Answer: Option A. -> reversible
:
A
From the figure, it is clear that water on freezing becomes ice and ice on melting becomes water.
So, both the states can be achieved by heating and cooling.
Hence, the given figure shows a reversible change.
Question 6. Which among the following is an example of a reversible change?
  1.    Making sand castle on beach
  2.    Making egg omelette
  3.    Burning petrol
  4.    Cutting of trees
 Discuss Question
Answer: Option A. -> Making sand castle on beach
:
A
Sand castles can be broken back to sand, so it is a reversible change.On the other hand, making egg omelette, cutting of trees and burning petrolare irreversible as they cannot be brought back to their original state.
Question 7. The burning of paper is a reversible change.
  1.    True
  2.    False
  3.    It is a periodic change.
  4.    It is a temporary change.
 Discuss Question
Answer: Option B. -> False
:
B
Reversible changes are changes which can be undone. When we burn a piece of paper it turns into ash. We cannot get the paper back from the ash. Hence, it is an irreversible change.
Question 8. Explain physical and chemical changes with examples. [5 MARKS]
 Discuss Question

:
Physical change: 2 Marks
Chemical change: 2 Marks
Examples: 1 Mark
Physical changes are the changes where the physical property of the substance varies without any formation of new products. These changes are reversible and the products are identical to the reactants.
Examples: Melting of ice,melting of wax.
Chemical changes are the changes where the chemical property of the substance varies with the formation of new products.These changes are irreversible and the products are not identical to the reactants.
Examples: Formation of curd from milk, rusting of iron.
Question 9. The leaves of a tree change their colour in spring before the shed. This is a reversible change.
  1.    True
  2.    False
 Discuss Question
Answer: Option B. -> False
:
B
During autumn, leaves change their colorso this is a change.
The natural colours of the leaves cannot be regained. Hence, it is an irreversible change.
Question 10. A piece of paper is used to make a paper plane. This is a ___________ change.
A Piece Of Paper Is Used To Make A Paper Plane. This Is A __...
 
  1.    reversible
  2.    irreversible
  3.    permanent
  4.    periodic
 Discuss Question
Answer: Option A. -> reversible
:
A
A reversible change is a change which can be undone.
When a paper is folded to make a paper plane, we have changed the shape of the paper. But, it is not permanent. We can unfold the paper and bring it back to its original shape. This makes it a reversible change.

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