Changes

Q.

Heating zinc oxide is a physical change. How?

. What is the colour of phenolphthalein acidic and basic media?

Q.

What happens to the chemical composition of the original substance during a chemical change?

Q.

Drying of leaves is an example of a change.

1. True

2. False

Q.

Photosynthesis is a physical or chemical change; reversible or Irreversible.

Clotting of blood is a physical or chemicalchange; reversible or Irreversible.

Liberation of oxygen occurs in the process of what

Inflation of a balloon is a physical or chemicalchange; reversible or Irreversible

Q.

Which of the following is the main characteristic of a chemical change?

1. A new substance is formed.

2. Shape is changed.

3. Size is changed.

4. State is changed.

Q.

State True/ False
You encounter a change when you switch on the tube light in your house.

1. False

2. True

Q. Identify the types of changes which occurs in the following image.

1. Natural
2. Man-made
3. Temporary
4. Permanent

Q.

You encounter a change when you switch on the tube light in your house.

1. True

2. False

Q. What are desirable and undesirable changes? Give examples.

Q. When an iron nail is added to acidic copper sulphate solution, the colour of the deposit on the iron nail is:

1. brown
2. blue
3. green
4. pink

Q.

Question 3.

Which of the following changes are Reversible and Irreversible?

(a) Blowing of a balloon

(b) Folding a paper to make a toy aeroplane

(c) Rolling a ball of dough to make roti

(d) Baking cake in an oven

(e) Drying a wet cloth

(f) Making biogas from cow dung

(g) Burning of a candle

Q. When a nail is added to acidic copper sulphate solution, the colour changes from _______.

1. blue to green
2. green to blue
3. blue to pink
4. pink to green

Q. Which among the following is not an example of irreversible change?

1. Rolling chapati from dough
   
2. Formation of flower from bud
   
3. Growth of plants
   
4. Curdling of milk
   

Q. The conversion of potato to potato wafers is a _______ change.

1. fast
2. temporary
3. permanent
4. natural

Q. Which of the following changes involves the formation of a new substance?

1. Boiling
2. Melting
3. Cooking
4. Freezing

Q.

Question 3.

Which of the following changes are Reversible and Irreversible?

(a) Blowing of a balloon

(b) Folding a paper to make a toy aeroplane

(c) Rolling a ball of dough to make roti

(d) Baking cake in an oven

(e) Drying a wet cloth

(f) Making biogas from cow dung

(g) Burning of a candle

Q. Which among the following is an irreversible change?

1. Freezing
2. Melting
3. Boiling
4. Rusting

Q. Statement 1: No New substance is formed during a physical change.

Statement 2: New substances are formed during chemical changes.

1. Both statements are true.
2. Both statements are false.
3. Only statement 1 is true.
4. Only statement 2 is true.

Q. Match the correct pairs.

1. 
2. 
3. 
4. 
5. 
6. 

Q. The process through which something becomes different is known as a .

1. change
2. extraction
3. destruction

Q. Vapours of ________ phosphorous burn when matchstick is struck against the matchbox.

1. White
2. Red
3. Orange
4. Brown

Q.

When leaves change their color during autumn and dry out, it's a change.

1. True

2. False

Q. Pair up the given changes with its respective type.

1. Reversible
2. Irreversible
3. 
4. 
5. Chemical
6. 

Q.

In my book, it is given that a green mass forms on the surface of copper when exposed to air due to the formation of copper oxide and basic copper carbonate whereas in this chapter it is given that the green mass is a mixture of copper hydroxide and copper carbonate. Is the material written in my book is incorrect and I should neglect it?

Q.

Question 1.

Differentiate:

1. Slow and Fast change

2. Natural and man-made change

Q. Change of seasons is a:

1. Chemical Change

2. Man-made change

3. Fast Change

4. Periodic Change

Q.

Which of the following is an example of a reversible change?

1. Cutting a piece of paper

2. Ripening of fruits

3. Grinding of grain into flour.

4. Making a light mark on a paper with a pencil

Q. Which among the following is not an example of a natural change?

1. Burning of fuels

2. Ageing of human
   

3. Ripening of fruit

4. Blooming of flower