a teacher wants to perform a classroom demonstration that illustrates both chemical and physical changes…

a teacher wants to perform a classroom demonstration that illustrates both chemical and physical changes. which would be the best demonstration that she could use?\n- bending a piece of aluminum\n- breaking a matchstick\n- dissolving sugar in water\n- burning a candle

a teacher wants to perform a classroom demonstration that illustrates both chemical and physical changes. which would be the best demonstration that she could use?\n- bending a piece of aluminum\n- breaking a matchstick\n- dissolving sugar in water\n- burning a candle

Answer

Brief Explanations:

  1. Bending a piece of aluminum is a physical change as only its shape changes and no new substance is formed.
  2. Breaking a matchstick is a physical change; it just divides the matchstick into parts without a chemical reaction.
  3. Dissolving sugar in water is a physical change; sugar disperses in water but no new chemical - substance is created.
  4. Burning a candle involves both physical and chemical changes. The melting of wax is a physical change (change of state from solid to liquid). The burning of the wax vapors and wick is a chemical change as new substances like carbon dioxide and water are formed along with heat and light.

Answer:

D. Burning a candle