Answer:
option C. Addition of protons to the atomic nucleus.
Explanation:
Elements are fundamentally made up of atoms. Atoms in turn has three sub particles.
These particles are; neutrons, electrons and protons.
The sub particles responsible for the mass of an atoms is basically the protons and neutrons. Going through the options;
The correct option is option C. Addition of protons to the atomic nucleus.
Saying I have two different compounds with different molecular formula. One is compound NaCl, the other one is compound H2O. They will have different chemical properties such as their melting and boiling point. Therefore the answer is Yes.
The rate of the reaction is measurable quantity that refers to the amount or how much is are chemical substances reagents used up or converted into the product over some period of time.
Rate = change in the amount/time.
This can indirectly be observed through many ways, such as the volume of gas given off if the byproduct is a gas being produced, the colour of the solution etc.
Well a question to ask would be if the mass of the material has changed significantly as that would determine that the substance is radioactive or if there have been any high readings found by a Geiger meter in certain period of time
hope that helps