Answers marked verified were checked during generation against the chapter context and source question text.
Your Progress - Chapter 30% complete
1I. Choose the Correct Answer5 questions
Q.1When ice melts to form water, change occurs in itsv
- A. position
- B. colour
- C. state
- D. composition
Q.2Drying of wet clothes in air is an example ofv
- A. Chemical change
- B. Undesirable change
- C. irreversible change
- D. physical change
Answer:(d) Physical change
Q.3Drying of wet clothes in air Is an example ofv
- A. Chemical change
- B. Undesirable change
- C. irreversible change
- D. physical change
Answer:(d) physical change
Q.4Out of the following an example of a desirable change ¡sv
- A. rusting
- B. change of seasons
- C. earthquake
- D. flooding
Answer:(b) change of seasons
Q.5Air pollution leading to Acid rain is av
- A. reversible change
- B. fast change
- C. natural change
- D. human made change
Answer:(d) human made change
2II. Fill in the blanks1 questions
Q.G1Magnet attracts iron needle. This is ……… change, (a reversible / an irreversible) Boiling of egg results in ………… change, (a reversible / an irreversible) Changes that are harmful to us are ………… (desirable / undesirable) Plants convert Carbon-di-oxide and water into starch. This is an example of ………. change, (natural / human made) Bursting of fire crackers is a ……….. change whereas germination of seeds is a ………. change, (slow / fast)v
Answer:a reversible
an irreversible
undesirable
Natural
fast; slow
3III. True or False. If False, give the correct statement1 questions
Q.G2Growing of teeth in an infant is slow change. Burning of match stick is a reversible change. Change of New moon to Full moon is human made. Digestion of food is a physical change. In a solution of salt in water, water is the solute.v
Answer:True
False – It is an irreversible change
False – It is a Natural change
False – It is a Chemical change
False – Water is the solvent
4IV. Analogy6 questions
Q.1Curdling of milk : irreversible change :: Formation of clouds : ……….. changev
Q.2Photosynthesis : ……….. change :: burning of coal : Human – made changev
Q.3Dissolving of glucose: reversible change :: Digestion of food : ………… changev
Q.4Cooking of food : desirable change :: decaying of food : ………… changev
Q.5Burning of matchstick: ………… change :: Rotation of the Earth : Slow changev
Q.2Touch me not plant: ………… : : digestion of food : Irreversible changev
5V. Circle the odd one out. Give reason for your choice4 questions
Q.1Growth of a child, Blinking of eye, Rusting, Germination of a seed.v
Answer:Blinking of eye (a fast change)
Q.2Glowing of a bulb, lighting of a Candle, breaking of a coffee mug, curdling of milk.v
Answer:Curdling of milk (a chemical change)
Q.3Rotting of an egg, condensation of water vapour, trimming of hair, Ripening of fruit.v
Answer:Trimming of hair (Man-made change)
Q.4Inflating a balloon, popping a balloon, fading of wall paint, burning of kerosenev
Answer:Burning of Kerosene (Chemical change)
6VI. Give a very short answer4 questions
Q.1What kind of change is associated with the decaying of plants?v
Answer:Decaying of plants is associated with slow change and chemical change.
Q.2You are given some candle wax. Can you make a candle doll from it? What kind of change is this?v
Answer:Yes, I can make a doll from the candle. The kind of change is a physical change.
Q.3Define a slow change.v
Answer:Changes which take place over a long period of time (hours/days/months/years) are known as slow changes.
Q.4What happens when cane sugar is strongly heated? Mention any two changes in it.v
Answer:When Cane sugar is strongly heated, it will initially melt and after that start to decompose. It will turn brown and then black and give off fumes.
The changes involved are:
Physical change
irreversible change
7VII. Give a short answer3 questions
Q.1What happens when the paper is burnt? Explain.v
Answer:When the paper is burnt, oxygen from the air combines with carbon in the paper turning into carbon dioxide and water vapor which float away, leaving solid ash. The action of burning paper can’t be reversed. So, it is an irreversible change. Also, it is a Chemical change and a Fast change.
Q.2Can deforestation be considered a desirable change? Explain.v
Answer:Deforestation cannot be considered a desirable change.
Because it is harmful to our environment and not desired by us are known as Undesirable changes.
Q.3What type of changes is associated with the germination of a seed? Explain.v
Answer:Germination of seed is a slow change.
Changes which take place over a long period of time (days) are known as Slow changes.
8VIII. Answer in detail1 questions
Q.1Give one example in each case that happens around you. (e) Desirable and undesirable changev
- A. Slow and fast change
- B. Reversible and irreversible change
- C. Physical and chemical change
- D. Natural and man-made change
9IX. Questions Based on Higher Order Thinking Skills (HOTS)2 questions
Q.1When a candle is lit the following changes are observed.v
Answer:Wax melts.
Candle keeps burning.
The size of the candle decreases.
The molten wax solidifies
Q.2Which of the changes can be reversed? Justify your answer.v
Answer:When the candle is burning, the heat of the flame melts the solid wax to liquid wax. This signifies reversible (or) Physical changes. Also, as the wax melts, the size of candle decreases. If then molten wax solidifies and takes a different shape.
10I. Choose the appropriate answer4 questions
Q.1Water changes into ice on cooling are called asv
- A. Melting
- B. Vaporisation
- C. Condensation
- D. Freezing
Q.2_______ is the process in which something becomes different from what it was earlier.v
- A. Classification
- B. Composition
- C. Position
- D. Change
Q.3Evaporation of water from lakes and riverv
- A. Slow change
- B. Fast change
- C. Natural change
- D. Both (a) and (b)
Answer:(d) Both (a) and (b)
Q.4_______ change is a temporary changev
- A. Physical
- B. Chemical
- C. Undesirable
- D. slow
11V. Very short answer2 questions
Q.2What is a reversible change?v
Answer:Changes which can be reversed (to get back to the original state) are known as reversible changes.
Q.4Water is the universal solvent. Why?v
Answer:Water is known as the universal solvent. It dissolves a wide range of substances.
12VI. Long answer1 questions
Q.1Distinguish between the physical and chemical changes.v