Question 9

Question

Are the following examples of chemical or physical changes?

Column A
1.
A silver spoon tarnishing:
A silver spoon tarnishing
2.
Blowing a dandelion:
Blowing a dandelion
3.
Building a sand castle:
Building a sand castle
4.
Toasting bread:
Toasting bread
Column B
a.Chemical change
b.Physical change

Answer 1

Here are the classifications for the changes in Column A:

1. A silver spoon tarnishing - a. Chemical change
   (This involves a chemical reaction between silver and sulfur compounds in the air, leading to the formation of silver sulfide.)

2. Blowing a dandelion - b. Physical change
   (This is a change in the physical state of the dandelion’s seeds being dispersed, but no new substance is formed.)

3. Building a sand castle - b. Physical change
   (This involves reshaping sand but does not alter the chemical composition of the sand itself.)

4. Toasting bread - a. Chemical change
   (This involves the Maillard reaction and caramelization, which change the chemical structure of the bread.)

So, the completed classifications would be:

1. a
2. b
3. b
4. a