Physical and Chemical Changes - AP Chemistry

1. Identify whether evaporating alcohol is a physical or chemical change.

   Physical change. Only state changes from liquid to gas.

2. What is sublimation?

   The transition of a substance from solid to gas without liquifying. Direct phase transition bypassing liquid phase.

3. Identify whether dissolving sugar in tea is a physical or chemical change.

   Physical change. Sugar molecules disperse but remain unchanged.

4. What is a physical change?

   A change affecting the form but not the chemical composition. Only molecular arrangement changes, not identity.

5. Is freezing water a physical or chemical change?

   Physical change. Only state changes from liquid to solid.

6. Is chopping wood a physical or chemical change?

   Physical change. Only size and shape change, not composition.

7. What are indicators of a chemical change?

   Color change, gas production, temperature change, precipitate formation. These signs indicate new substances are forming.

8. What is the result of a chemical reaction?

   Formation of new substances with different properties. Products have different molecular structures than reactants.

9. What type of change is dissolving salt in water?

   Physical change. Salt molecules disperse but remain chemically unchanged.

10. Identify whether mixing vinegar and baking soda is a physical or chemical change.

    Chemical change. Acid-base reaction produces gas and new compounds.

11. Is breaking a glass a physical or chemical change?

    Physical change. Only shape changes, glass composition stays same.

12. What is a chemical change?

    A change where a substance transforms into a new substance. New molecular bonds form, creating different substances.

13. Identify whether grinding coffee beans is a physical or chemical change.

    Physical change. Only size changes, coffee composition unchanged.

14. Identify whether melting ice is a physical or chemical change.

    Physical change. Only state changes from solid to liquid.

15. Identify whether boiling water is a physical or chemical change.

    Physical change. Only state changes from liquid to gas.

16. Explain the term 'chemical property'.

    A trait observed in a substance undergoing a chemical change. Describes reactivity and behavior during reactions.

17. What is a precipitate in a chemical reaction?

    An insoluble solid formed from a solution. Forms when dissolved ions recombine and crystallize.

18. Identify whether photosynthesis is a physical or chemical change.

    Chemical change. $CO_2$ and glucose form from light energy and reactants.

19. What is combustion?

    A chemical process of burning, involving oxygen and fuel. Oxidation reaction that releases energy as heat.

20. Identify whether crushing a can is a physical or chemical change.

    Physical change. Only shape changes, aluminum composition unchanged.

21. What type of change is burning wood?

    Chemical change. Combustion produces new compounds like $CO_2$ and $H_2O$.

22. What is the law of conservation of mass?

    Mass is neither created nor destroyed in a chemical reaction. Total mass of reactants equals total mass of products.

23. Identify whether fermenting grapes is a physical or chemical change.

    Chemical change. Sugars convert to alcohol through enzyme reactions.

24. What occurs during a phase change?

    Transition between different states of matter. Molecular arrangement changes but identity remains.

25. Is souring milk a physical or chemical change?

    Chemical change. Bacteria produce acids that change milk composition.

26. What is deposition in terms of phase change?

    Gas to solid transition. Vapor condenses directly to solid state.

27. Identify whether digestion of food is a physical or chemical change.

    Chemical change. Enzymes break down molecules into new compounds.

28. What is the main difference between physical and chemical changes?

    Physical changes do not alter chemical composition; chemical changes do. Chemical composition determines the type of change.

29. Identify whether rusting iron is a physical or chemical change.

    Chemical change. Iron reacts with oxygen to form iron oxide.

30. Is cooking an egg a physical or chemical change?

    Chemical change. Heat denatures proteins, forming new structures.

31. Identify whether bending a metal rod is a physical or chemical change.

    Physical change. Only shape changes, metal composition unchanged.

32. What does a chemical equation represent?

    Reactants turning into products in a chemical reaction. Shows molecular rearrangement during reactions.

33. Identify whether bleaching a stain is a physical or chemical change.

    Chemical change. Bleach chemically alters the stain molecules.

34. What is a physical property?

    A characteristic that can be observed without changing substance identity. Observable without altering molecular composition.

35. Identify whether frying an egg is a physical or chemical change.

    Chemical change. Heat denatures proteins in the egg.

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