Question

1. A metal surface becomes dull because of continued abrasion.

a) Physical Change
b) Chemical Change

2. A ballon filled with hydrogen gas explodes upon contact with the spark.

a) Physical Change
b) Chemical Change

3. Copper turns green on exposure to air and water.

a) Physical Change
b) Chemical Change​

Answer 1

Answer:

1- chemical change

2-chemical change

3-phusical change

Answer 2

Answer:

1)b

2)a

3)a

Explanation:

read this chapter in 7th science book