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20 questions
A change in which a substance undergoes changes in its physical properties is called _____.
chemical change
physical change
irreversible change
biological change
Browning of an apple after it is cut is an example of ____.
physical change
chemical change
reversible change
biological change
When Magnesium ribbon is burnt in oxygen, the product obtained is ___.
Magnesium chloride
Magnesium sulphate
Magnesium carbide
Magnesium oxide
When Magnesium ribbon is ignited using a candle flame, it burns with a __________.
sparkling red light
dull yellow light
bright green light
brilliant white light
Which of the following is a physical change?
Rusting of iron
Melting of wax
Burning of coal
Curdling of milk
Which of the following is a chemical change?
Twinkling of stars
Cutting of fruits
Cooking of vegetables
Boling of water
A chemical change may involve ____________.
change in color only
change in temperature only
evolution of gas only
all of the above
Which of the following is/are true when milk changes to curd?
(i) Its state is changed from liquid to semi solid
(ii) It changes color
(iii) It changes taste
(iv) The change cannot be reversed.
Choose the correct option from the ones given below:
(i) and (ii) are correct
(ii) and (iii) are correct
(i), (iii) and (iv) are correct
All are correct
Which of the following is incorrect for a chemical reaction?
Heat may be given out but never absorbed
Sound may be produced
A color change may take place
A gas may be evolved
Which of the following is false?
When a candle burns, both physical and chemical changes take place.
Stretching of a rubber band is not a physical change
Melting of ice is a physical change
Dissolving common salt in water is not a chemical change
The gas that we use in the kitchen is liquefied petroleum gas (LPG). In a cylinder, it exists as a liquid. When it is released from the cylinder it becomes a gas (Change A), and then it burns (Change B). Which of the following is true?
Process A is a Physical Change
Process B is a Chemical change
Both processes A and B are chemical changes
Both (a) and (b) are True
Anaerobic bacteria digest the animal waste and produce biogas (Change A). The gas is burnt as fuel (Change B). The following statements pertain to these changes. Choose the correct one.
Process A –Physical Change
Process B- Chemical change
Both process A and B are chemical changes
Both process A and B are physical change
A physical change is named as such because __________.
it involves changes in physical properties of a substance
it is accompanied by a transfer of energy
it is a reversible process
it involves the formation of new products
A change in which the original substance can be regained by a change in conditions is called _____________.
a reversible change
a physical change
a chemical change
both (a) and (b)
Expansion on heating and contraction on cooling of metals are examples of ___________.
chemical changes
physical changes
irreversible changes
permanent changes
Melting and boiling point are ______________ properties of a substance.
physical
chemical
structural
external
“Adding salt to water changes the taste of water.” Which of the following statements is true regarding this change?
It is a chemical change because a new substance is formed.
It is a physical change because the original substance can be recovered
It is a chemical change because the salt cannot be recovered.
It is a physical change because there is a slight change in colour.
Pooja took a candle in a vessel and heated the vessel. Even though the candle did not burn, it changed its shape and state. What kind of change is this?
Irreversible change
Physical change
Chemical change
Permanent change
Which of the following is a physical change?
Burning of kerosene
Lighting an electric bulb
Heating sugar in a pan
Heating sulphur with iron filings to a red-hot state
On the basis of the following diagrams/pictures, answer the question given thereafter. Which of the following changes represent a chemical change?
Only (i)
Only (ii)
(i) and (ii)
Neither
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