Question

1. Give one example for each of the following types of changes:
a. physical changes
b. chemical changes
and irreversible changes taking place in the process.
3. Breaking of a glass tumbler and burning of paper are changes in which we cannot get back
the original substances. What is the difference between these two changes?
4. What kind of change is cooking of food? Why?
5. Do you agree with the statement ‘all physical changes are reversible”? If not give the correct
statement.
6. Growth is increase in size. Is it a physical or a chemical change? Give reasons.
D. LONG-ANSWER QUESTIONS: Answer these questions.
1. Explain the difference between physical and chemical changes, giving one example of each.
2. 'One way changes are classified is reversible and irreversible'. Explain with examples.
3. What is a chemical reaction? Explain with an example.
4. Give one example to show that when substances are mixed, it may result in a chemical or a
physical change depending on the conditions,
5. When a candle burns, both physical and chemical changes occur. Explain.
C. SHORT-ANSWER QUESTIONS: Answer in a sentence or two.
c. reversible changes d. irreversible changes
2. A potter shapes pots out of clay. He then bakes the pots in an oven. Identify the reversible​

Answer 1

Answer:

a. sublimation

b. burning of paper.

d. chemical change

e. true ,all physical changes are reversible

D. 1) physical: no new substance are formed.

example:drying of wet cloth

chemical : new susbtance with different composition and properties are formed.

example: rusting of iron .

3. the change that is permanent . example: burning of paper