Question

to determine whether a chemical reaction has taken place, a scientist can observe the properties of substances before and after a change has occurred. which property is unique for each substance in its purest form?
a. density
b. solubility
c. temperature
d. state
e. color

Explanation:

Density is a characteristic property of a pure substance and remains the same regardless of the amount of the substance. It is unique for each pure - substance and can be used to identify substances and determine if a chemical reaction has occurred as it is not easily changed by physical means alone. Solubility can change with temperature and other factors, temperature is a non - characteristic property that can vary widely, state can change with temperature and pressure (physical changes), and color can also be affected by physical factors or impurities.

Answer:

A. density