Question
Part 1: Identify Physical and Chemical Changes.
Images to Investigate
Does the image show a physical change or a chemical change?
What evidence can you provide to support that a chemical or a physical change has occurred?
These separated tobacco leaves have been exposed to air in the environment.
The chemist is adding 2 liquids together that burst into flames.
A person holding a piece of gallium metal, which starts to melt at body temperature.
Part 2: Explain your Understanding.
Write a paragraph explaining your understanding of physical and chemical changes. Provide a specific example of each and explain the evidence that supports your analysis that a physical or chemical change has occurred.
Images to Investigate
Does the image show a physical change or a chemical change?
What evidence can you provide to support that a chemical or a physical change has occurred?
These separated tobacco leaves have been exposed to air in the environment.
The chemist is adding 2 liquids together that burst into flames.
A person holding a piece of gallium metal, which starts to melt at body temperature.
Part 2: Explain your Understanding.
Write a paragraph explaining your understanding of physical and chemical changes. Provide a specific example of each and explain the evidence that supports your analysis that a physical or chemical change has occurred.
Answers
GPT-4o mini
### Part 1: Identify Physical and Chemical Changes
1. **Separated Tobacco Leaves Exposed to Air**
**Change Type:** Physical Change
**Evidence:** The tobacco leaves have undergone a physical change as they have merely been separated and exposed to air. The fundamental composition and structure of the tobacco leaves remain the same; they have not transformed into a different substance. Any browning or drying that occurs would be a result of moisture loss, not a transformation into a new chemical substance.
2. **Chemist Adding Two Liquids Together that Burst into Flames**
**Change Type:** Chemical Change
**Evidence:** The addition of two liquids that result in flames indicates a chemical reaction has occurred. The burning suggests that a new substance is formed (combustion), and there is typically an energy release during such reactions, seen in the form of heat or light. This change cannot simply be reversed, unlike physical changes, as new chemical entities are obtained.
3. **Person Holding a Piece of Gallium Metal That Starts to Melt at Body Temperature**
**Change Type:** Physical Change
**Evidence:** The gallium metal melting is a clear example of a physical change since it is simply transitioning from a solid to a liquid state. The gallium maintains its chemical identity throughout this process; no new substances are formed, and when cooled, it can revert back to a solid form, demonstrating that the change is reversible.
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### Part 2: Explain your Understanding
Physical and chemical changes are two fundamental concepts in chemistry that describe how substances interact and transform. A physical change involves alterations in form or state without changing the chemical composition of a substance. For example, the melting of ice into water is a physical change; ice remains H₂O whether it's solid or liquid, and the change is reversible. On the other hand, a chemical change results in the formation of new substances with different chemical properties, often involving reactions such as combustion or rusting. A classic example of a chemical change is the reaction between vinegar and baking soda, which produces carbon dioxide gas; the formation of bubbles indicates that a new substance is produced. The evidence supporting a chemical change includes temperature changes, color changes, or the production of gas, all of which signal that a chemical reaction has occurred, leading to new entities that cannot revert to their original forms simply.
1. **Separated Tobacco Leaves Exposed to Air**
**Change Type:** Physical Change
**Evidence:** The tobacco leaves have undergone a physical change as they have merely been separated and exposed to air. The fundamental composition and structure of the tobacco leaves remain the same; they have not transformed into a different substance. Any browning or drying that occurs would be a result of moisture loss, not a transformation into a new chemical substance.
2. **Chemist Adding Two Liquids Together that Burst into Flames**
**Change Type:** Chemical Change
**Evidence:** The addition of two liquids that result in flames indicates a chemical reaction has occurred. The burning suggests that a new substance is formed (combustion), and there is typically an energy release during such reactions, seen in the form of heat or light. This change cannot simply be reversed, unlike physical changes, as new chemical entities are obtained.
3. **Person Holding a Piece of Gallium Metal That Starts to Melt at Body Temperature**
**Change Type:** Physical Change
**Evidence:** The gallium metal melting is a clear example of a physical change since it is simply transitioning from a solid to a liquid state. The gallium maintains its chemical identity throughout this process; no new substances are formed, and when cooled, it can revert back to a solid form, demonstrating that the change is reversible.
---
### Part 2: Explain your Understanding
Physical and chemical changes are two fundamental concepts in chemistry that describe how substances interact and transform. A physical change involves alterations in form or state without changing the chemical composition of a substance. For example, the melting of ice into water is a physical change; ice remains H₂O whether it's solid or liquid, and the change is reversible. On the other hand, a chemical change results in the formation of new substances with different chemical properties, often involving reactions such as combustion or rusting. A classic example of a chemical change is the reaction between vinegar and baking soda, which produces carbon dioxide gas; the formation of bubbles indicates that a new substance is produced. The evidence supporting a chemical change includes temperature changes, color changes, or the production of gas, all of which signal that a chemical reaction has occurred, leading to new entities that cannot revert to their original forms simply.