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.
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:
- Change in the color of the resulting mixture
- Precipitate or solid substance is formed
- Production of gas is visible through the formation of bubbles
- 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.