Slow Changes and Fast Changes

Q.

Write the characteristics of a physical change.

Q.

What is a natural change ?

Q. State whether the following are physical or chemical changes.
(r) Boiling of an egg

Q. Why interconversion of states of matter is considered as a physical change?

Q.

When ice melts to form water, then a change occurs in its

1. position

2. temperature

3. state

4. composition

Q.

Give an example of a physical change which occurs by the action of heat.

Q. What do you observe when: (a) water is boiled

Q. What do you observe when:
(d) solid ammonium chloride is heated

Q. What do you observe when: (c) some ice cubes are kept in a glass tumbler

Q.

Define slow changes.Give examples.

Q.

Define non-periodic changes.Give examples.

Q. State whether the following are physical or chemical changes.
(g) water cycle in nature

Q. Define:

(b) Brownian motion

Q. Match the following.

(a) Evaporation of water	(i) Non-periodic change
(b) Milk turning sour	(ii) Periodic change
(c) Earthquake	(iii) Chemical change
(d) Change of seasons	(iv) Physical change
(e) Glowing of bulb	(v) Reversible change

Q. Define:
(i) a physical change

Q.

Sheela cooked rice in a rice cooker. What kind of change took place?
(i) irreversible change
(ii) Slow change
(iii) natural change

1. Only (ii) and (iii)

2. Only (i) and (iii)

3. (i), (ii) and (iii)

4. Only (i) and (ii)

Q. Assertion: Burning of paper is a permanent change.
Reason: The products formed on burning of paper cannot be converted back to paper.

1. Both assertion and reason are true. Reason is the correct explanation of assertion.
2. Both assertion and reason are true. Reason is not the correct explanation of assertion.
3. Assertion is true but reason is false.
4. Assertion is false but reason is true.

Q. State whether the following are physical or chemical changes.
(e) burning of wood

Q. Write true or false against the following statements:
(d) Melting of ice is a physical change.

Q.

Which of the following properties of a substance does not change in a physical changes?

1. Chemical composition

2. shape

3. size

4. State

Q.

Statement 1: Melting is a physical change because melting doesn't create a new substance. It only changes the state of the wax from solid to liquid.
Statement 2: Burning is a chemical change because once wax is burnt, the wax gets converted to new substances.

Which of these statements is correct?

1. Statement 1 is correct

2. Statement 2 is correct

3. Both 1 and 2 are correct

4. None of these

Q. State whether the following are physical or chemical changes.
(k) dissolving sugar in water

Q.

Define chemical weathering.

Q.

________________________ changes are usually reversible in nature.

Q. Give two examples for chemical changes.

Q.

Question 1: germination of seeds is considered a dash change .

Q. State whether the following are physical or chemical changes.
(n) cutting wood into small pieces

Q.

Sublimation of iodine is an example of _______ [physical/chemical] change.

Q. State four differences between physical and chemical changes

Q. State whether the following are physical or chemical changes.
(q) Melting of wax