Question

2. A science teacher demonstrated physical and chemical changes by using a fork to hold a marshmallow over a lit candle. Which observation is the best evidence of a chemical change? a. Some candle wax melted b. Metal in the fork became warmer c. The marshmallow became sticky on the inside d. The marshmallow developed a brown crust on the outside

Answer 1

Answer:

Answer is option D

Explanation:

Chemical change is a change where a new substance is formed

Answer 2

The observation which is the best evidence of a chemical change is :

(d) The marshmallow developed a brown crust on the outside.

- Melting of candle wax is a physical change.

- Warming metal of fork is also a physical change.

- The marshmallow becoming sticky on the inside is also a physical change

- In all the above 3 processes, no new substance is formed.

- But on heating, the marshmallow develops a brown crust on the outside.

- Since a new substance is formed, so it is a chemical change.