Question

Which is the least reliable indicator of a chemical change?

change of color

change of odor

formation of gases

change of shape

Answer 1

1: a chemical change

2: the components of the pure substance will not be able to be separated by physical means

3: true

4: false

5:change of shape

6:a chemical change

7: false

8:false

9:solid

10: It reacts with hydrogen to form a gas.

11:false

12: false

Answer 2

I think the correct answer from the choices listed above is the last option. The least reliable indicator of a chemical change would be a change in shape. It does not indicate that a reaction happened. It can be that the substance was cut or crushed only. Hope this answers the question.