Question

The images show two processes. Image A: a roasting marshmallow, Image B: melting ice. Which statement about the two images is true?
1. Image A shows a physical change, and image B shows a chemical reaction.
2. Image A shows a chemical reaction, and image B shows a physical change.
3. Both images show chemical reactions that are endothermic.
4. Both images show chemical reactions that are exothermic.

Answer 1

Answer: 2. Image A shows a chemical reaction, and image B shows a physical change.

Explanation: A. Chemical change is defined as a change in which rearrangement of atoms take place and leads to formation of new substances.

Roasting of marshmallows will take place in the presence of oxygen and thus the marshmallows will be oxidized.

B.  Physical change is defined as a change which leads to change in shape, size or state of the substance changes. No new substance is formed.

Melting of ice only changes the phase of $H_2O$ from solid to liquid form and thus is a physical change.

$H_2O(s)\rightarrow H_2O(l)$

Answer 2

The correct answer would be the 2nd option Image A shows a chemical reaction, and image B shows a physical change.