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Type: Multiple-Choice
Category: Reactions
Level: Grade 8
Author: doliver701
Last Modified: 7 years ago

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Grade 8 Reactions

During science lab, some students added small pieces of magnesium (Mg) to hydrochloric acid (HCl). They noticed that bubbles formed, the test tube got hot, and the magnesium disappeared.

Which of the following is a sign that a chemical reaction has taken place in this experiment?
  1. odor
  2. formation of a gas
  3. decrease in temperature
  4. formation of a precipitate