Based on the concepts of chemical and physical changes, we can evaluate the statements given:
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Burning campfire wood is a chemical change. - True. When wood burns, it undergoes a chemical transformation, producing ash, smoke, and various gases.
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Toasting marshmallows results in a chemical change. - True. When marshmallows are toasted, the sugars caramelize and undergo a chemical change due to the heat.
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Burning campfire wood is a physical change. - False. Burning wood alters its chemical structure, which is characteristic of a chemical change.
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Toasting marshmallows results in a physical change only. - False. The process of toasting marshmallows involves both physical (melting) and chemical changes (cooking and caramelization).
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The heat produced by the fire chemically changes the surrounding air. - True. The heat can cause changes in the air, such as the formation of carbon dioxide and water vapor from combustion.
True Statements:
- Burning campfire wood is a chemical change.
- Toasting marshmallows results in a chemical change.
- The heat produced by the fire chemically changes the surrounding air.