the images show two processes. image a: a roasting marshmallow image b: melting ice which statement about…
the images show two processes. image a: a roasting marshmallow image b: melting ice which statement about the two images is true? image a shows a physical change, and image b shows a chemical reaction. image a shows a chemical reaction, and image b shows a physical change. both images show chemical reactions that are endothermic. both images show chemical reactions that are exothermic.
Answer
Explanation:
Step1: Define physical and chemical changes
A physical change is a change in the form or state of matter without changing its chemical composition. A chemical reaction is a process that leads to the transformation of one set of chemical substances to another.
Step2: Analyze Image A
Roasting a marshmallow involves a chemical reaction. The heat causes the sugars in the marshmallow to undergo a chemical change (caramelization and combustion), forming new substances with different chemical properties.
Step3: Analyze Image B
Melting ice is a physical change. Ice (solid - water) changes to liquid water. The chemical composition of water ($H_2O$) remains the same, only the state of matter changes from solid to liquid.
Step4: Analyze endothermic and exothermic nature
Roasting a marshmallow is an endothermic process as it requires heat input. Melting ice is also an endothermic process as heat is absorbed to break the intermolecular forces holding the ice together. But the key difference between the two processes is the type of change (physical vs chemical).
Answer:
Image A shows a chemical reaction, and image B shows a physical change.