No, changes in color or state and changes in temperature do not always indicate a chemical reaction. These changes can also be due to physical processes, such as changes in pressure, temperature.
For example, when ice (solid) is heated, it changes into water (liquid) without any chemical reaction occurring. Similarly, when water is heated, it changes into steam (gas) without any chemical reaction occurring. In both cases, the change in state is a physical change, not a chemical change.
So, while changes in color or temperature can sometimes indicate a chemical reaction, it is not always the case.
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Answer:
No, changes in color or state and changes in temperature do not always indicate a chemical reaction. These changes can also be due to physical processes, such as changes in pressure, temperature.
For example, when ice (solid) is heated, it changes into water (liquid) without any chemical reaction occurring. Similarly, when water is heated, it changes into steam (gas) without any chemical reaction occurring. In both cases, the change in state is a physical change, not a chemical change.
So, while changes in color or temperature can sometimes indicate a chemical reaction, it is not always the case.