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A girl mixed two substances together and concluded that a chemical reaction had taken...

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a046408 | eNotes Newbie

Posted June 13, 2013 at 12:21 PM via web

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A girl mixed two substances together and concluded that a chemical reaction had taken place. Explain how she was able to conclude that a chemical reaction occurred. In your explanation, be sure to include any evidence that would support the her conclusion.

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jerichorayel | College Teacher | (Level 1) Senior Educator

Posted June 13, 2013 at 5:43 PM (Answer #1)

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A chemical reaction is a process where in a certain chemical substance (or substances) is changed to form another kind of substance (or substances). There are different manifestations in order to conclude that a chemical reaction took place. Here are some of the possible indications of a chemical reaction taking place:

  1. Change in the color of the resulting mixture
  2. Precipitate or solid substance is formed
  3. Production of gas is visible through the formation of bubbles
  4. There is an increase or decrease in temperature

These evidences are enough to say that a chemical reaction took place. However, not all of the four evidences may be evident in a certain reaction. For example, you mixed two colourless liquids and the temperature increases with the formation of bubbles. Though it does not form precipitates, it is safe to say that a chemical reaction took place. 

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