Chemistry

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Chemical reaction creating materials with color changes.

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Background Information

You know a chemical reaction takes place if one or more of these occur:

1. Color changes - Different combinations of molecules reflect light differently. A color change indicates a change in molecules.

2. Heat content changes - In all chemical reactions, the heat content of the reactants and the content of the products is never the same. Sometimes the difference is great and can be easily detected; at other times the difference is slight and is more difficult to detect.

3. A gas is produced - Whenever a gaseous product forms in a liquid solution, bubbles can be seen. A colorless gas produced in a reaction of solids is much harder to detect.

4. A precipitate forms - Precipitates are insoluble products formed by a reaction taking place in a liquid solution. This insoluble product will eventually settle to the bottom, but might immediately appear by turning the clear solution cloudy.

In the demonstration part of this activity, you will be mixing compounds. Compounds based on the following, to create a gas or a change in color or formation of a precipitate.

1- KI + AgNO₃

2- NaOH + CuSO₄

3NaOH + AgNO₃

To demonstrate that evidence of a chemical reaction and chemical change can sometimes be seen by the production of a gas or a change of color of a solution.

To show evidence that a chemical reaction and chemical change.

Chemical reactions, resulting in chemical changes, occur when certain substances are mixed together. Evidence of a chemical reaction may include production of a gas, a change in color, a change in temperature, or formation of a precipitate.