Which is the least reliable indicator of a chemical change?

change of color

change of odor

formation of gases

change of shape

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.

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

Explanation:

There are some options that are correct.

1) Amount of limiting reactant used in a reaction.

It can be calculated from the quantity of the reactants.

2) Amount of excess reactant from a reaction

It can be also calculated from the quantity of the reactants.

3) Theoretical yield of products

Amount of limiting reactant used in a reaction

Amount of excess reactant from a reaction

Theoretical yield of products