6th Grade > Chemistry
CHANGES AROUND US MCQs
Total Questions : 97
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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.
Answer: Option B. -> reversible , irreversible
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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.
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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.
Answer: Option A. -> Irreversible and physical
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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.
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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.
Answer: Option A. -> True
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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.
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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.
Answer: Option A. -> reversible
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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.
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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.
Answer: Option A. -> Making sand castle on beach
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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.
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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.
Answer: Option B. -> False
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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.
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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.
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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.
Answer: Option B. -> False
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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.
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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.
Answer: Option A. -> reversible
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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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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.