Question

complete the following statements. • the chemical properties of a substance can be observed changing the identity of a substance. • an example of a chemical property is

Explanation:

First Statement:

Step1: Recall chemical property observation

Chemical properties require a chemical change (which changes the substance's identity) to be observed. So we need "only by" here as chemical properties can't be seen without changing the substance.
<The first blank: only by>

Second Statement (Example of Chemical Property):

Step1: Identify chemical property examples

Chemical properties include reactivity (like flammability, reactivity with acids, etc.). For example, flammability (a substance's ability to burn, which involves a chemical change) is a chemical property. Other examples could be reactivity with oxygen, ability to rust, etc.
<An example could be flammability (or reactivity with acid, ability to rust, etc.)>

Answer:

• The chemical properties of a substance can be observed $\boldsymbol{\text{only by}}$ changing the identity of a substance.
• An example of a chemical property is $\boldsymbol{\text{flammability}}$ (or other valid chemical property like "reactivity with acid", "ability to rust", etc.).