Question

which of the following demonstrate evidence of a chemical change? select the correct answer in each row.
table columns: substance sinking, precipitate forming, change in shape, production of gas, change in volume, production of light; rows: chemical change occurred, chemical change has not occurred; each cell contains a radio button (circle).

Explanation:

• Substance sinking: This is a physical change (related to density and buoyancy, no new substance formed), so "Chemical Change Has Not Occurred".
• Precipitate forming: Formation of a precipitate indicates a chemical reaction (new insoluble substance), so "Chemical Change Occurred".
• Change in shape: Physical change (like bending, no new substance), so "Chemical Change Has Not Occurred".
• Production of gas: If gas is produced via a reaction (e.g., acid - metal), it's a chemical change, so "Chemical Change Occurred".
• Change in volume: Physical change (e.g., expansion/contraction, no new substance), so "Chemical Change Has Not Occurred".
• Production of light: If from a chemical reaction (e.g., combustion, bioluminescence), it's a chemical change, so "Chemical Change Occurred".

Answer:

• Substance sinking: Chemical Change Has Not Occurred
• Precipitate forming: Chemical Change Occurred
• Change in shape: Chemical Change Has Not Occurred
• Production of gas: Chemical Change Occurred
• Change in volume: Chemical Change Has Not Occurred
• Production of light: Chemical Change Occurred