Chemical vs Physical Changes - Middle School Physical Science
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What is the best evidence that a chemical reaction has occurred: change in shape or formation of a new substance?
What is the best evidence that a chemical reaction has occurred: change in shape or formation of a new substance?
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Formation of a new substance. New substances prove atoms rearranged into different molecules.
Formation of a new substance. New substances prove atoms rearranged into different molecules.
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Identify the change type: sugar dissolving in water to make a sugar solution.
Identify the change type: sugar dissolving in water to make a sugar solution.
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Physical change. Sugar molecules disperse but remain chemically unchanged.
Physical change. Sugar molecules disperse but remain chemically unchanged.
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What is the key particle-level difference between chemical and physical changes?
What is the key particle-level difference between chemical and physical changes?
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Chemical: bonds change; physical: bonds stay the same. Chemical changes break/form bonds; physical changes don't.
Chemical: bonds change; physical: bonds stay the same. Chemical changes break/form bonds; physical changes don't.
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Which observation indicates a chemical reaction: a new odor produced or a smell released by opening a container?
Which observation indicates a chemical reaction: a new odor produced or a smell released by opening a container?
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A new odor produced. New molecules often have different odors than original substances.
A new odor produced. New molecules often have different odors than original substances.
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Which observation suggests a chemical reaction: temperature change without heating/cooling or temperature change from a hot plate?
Which observation suggests a chemical reaction: temperature change without heating/cooling or temperature change from a hot plate?
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Temperature change without external heating/cooling. Chemical reactions release or absorb energy, changing temperature.
Temperature change without external heating/cooling. Chemical reactions release or absorb energy, changing temperature.
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Which observation indicates a chemical reaction: light produced by a glow stick or light reflected from a mirror?
Which observation indicates a chemical reaction: light produced by a glow stick or light reflected from a mirror?
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Light produced by a glow stick. Chemical energy converts to light energy in the reaction.
Light produced by a glow stick. Chemical energy converts to light energy in the reaction.
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Which sign is strongest evidence of a chemical reaction: a color change after mixing or a color change from dye added?
Which sign is strongest evidence of a chemical reaction: a color change after mixing or a color change from dye added?
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Color change after mixing (not from dye). Color from new substances differs from simple dye mixing.
Color change after mixing (not from dye). Color from new substances differs from simple dye mixing.
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Which type of change forms at least one new substance with a new chemical composition?
Which type of change forms at least one new substance with a new chemical composition?
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Chemical change (chemical reaction). New substances have different chemical formulas and properties than the original.
Chemical change (chemical reaction). New substances have different chemical formulas and properties than the original.
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Identify the change type: ice melting into liquid water.
Identify the change type: ice melting into liquid water.
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Physical change. H₂O molecules remain intact, only arrangement changes.
Physical change. H₂O molecules remain intact, only arrangement changes.
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Identify the change type: water freezing into ice.
Identify the change type: water freezing into ice.
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Physical change. Same H₂O molecules, just organized into solid structure.
Physical change. Same H₂O molecules, just organized into solid structure.
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Identify the change type: water boiling into water vapor.
Identify the change type: water boiling into water vapor.
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Physical change. H₂O stays H₂O, molecules just spread farther apart.
Physical change. H₂O stays H₂O, molecules just spread farther apart.
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Identify the change type: paper being cut into smaller pieces.
Identify the change type: paper being cut into smaller pieces.
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Physical change. Paper composition unchanged, only size and shape altered.
Physical change. Paper composition unchanged, only size and shape altered.
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Which option is physical, not chemical: condensation on a cold cup or tarnishing of silver?
Which option is physical, not chemical: condensation on a cold cup or tarnishing of silver?
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Condensation on a cold cup. Water vapor changes to liquid; silver forms new compound Ag₂S.
Condensation on a cold cup. Water vapor changes to liquid; silver forms new compound Ag₂S.
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Identify the change type: iron rusting to form iron oxide.
Identify the change type: iron rusting to form iron oxide.
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Chemical change. Iron atoms bond with oxygen to form new compound Fe₂O₃.
Chemical change. Iron atoms bond with oxygen to form new compound Fe₂O₃.
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Identify the change type: vinegar and baking soda reacting and producing bubbles.
Identify the change type: vinegar and baking soda reacting and producing bubbles.
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Chemical change. Acid-base reaction produces new substances: CO₂ gas and salts.
Chemical change. Acid-base reaction produces new substances: CO₂ gas and salts.
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Identify the change type: wood burning to produce ash and gases.
Identify the change type: wood burning to produce ash and gases.
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Chemical change. Cellulose breaks down into CO₂, H₂O, and carbon (ash).
Chemical change. Cellulose breaks down into CO₂, H₂O, and carbon (ash).
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Identify the process: ice melts into liquid water. Chemical or physical change?
Identify the process: ice melts into liquid water. Chemical or physical change?
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Physical change. Same substance ($H_2O$) in different state, no new substance forms.
Physical change. Same substance ($H_2O$) in different state, no new substance forms.
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What type of change forms one or more new substances with new properties?
What type of change forms one or more new substances with new properties?
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Chemical change (chemical reaction). New substances have different chemical compositions and properties.
Chemical change (chemical reaction). New substances have different chemical compositions and properties.
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What type of change alters form or state but does not create a new substance?
What type of change alters form or state but does not create a new substance?
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Physical change. The substance's identity remains the same, only appearance changes.
Physical change. The substance's identity remains the same, only appearance changes.
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Which evidence most directly indicates a chemical reaction: a new substance forming or a shape change?
Which evidence most directly indicates a chemical reaction: a new substance forming or a shape change?
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A new substance forming. New substances indicate chemical bonds have rearranged.
A new substance forming. New substances indicate chemical bonds have rearranged.
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Identify the evidence: bubbling occurs because a gas forms during a process. Chemical or physical change?
Identify the evidence: bubbling occurs because a gas forms during a process. Chemical or physical change?
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Chemical change. Gas formation indicates new substances with different properties.
Chemical change. Gas formation indicates new substances with different properties.
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Identify the process: water boils into water vapor. Chemical or physical change?
Identify the process: water boils into water vapor. Chemical or physical change?
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Physical change. Water remains $H_2O$ in both liquid and gas states.
Physical change. Water remains $H_2O$ in both liquid and gas states.
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Identify the process: water vapor condenses into liquid water. Chemical or physical change?
Identify the process: water vapor condenses into liquid water. Chemical or physical change?
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Physical change. Same $H_2O$ molecules, just changing from gas to liquid state.
Physical change. Same $H_2O$ molecules, just changing from gas to liquid state.
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Identify the process: sugar dissolves in water to form a solution. Chemical or physical change?
Identify the process: sugar dissolves in water to form a solution. Chemical or physical change?
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Physical change. Sugar molecules remain intact, just dispersed in water.
Physical change. Sugar molecules remain intact, just dispersed in water.
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Identify the process: a piece of paper is cut into smaller pieces. Chemical or physical change?
Identify the process: a piece of paper is cut into smaller pieces. Chemical or physical change?
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Physical change. Paper's chemical composition unchanged, only size differs.
Physical change. Paper's chemical composition unchanged, only size differs.
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