If you need to identify a material without changing the object in anyway, should you use physical or chemical properties?

you need to identify the materials in an object without changing the object in any way. Should you use physical or chemical properties to identify the material? Explain your choice. You should us physical properties because if you used chemical properties, you would have changed the material in the object.

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the electrical  conductivity  of asolution  of an electrolyte is measured by determining the resistance of thesolution  between two flat or cylindrical electrodes separated by a fixed distance.