In a chemical reaction how does the mass of the reactants compare with the mass of the products?

The mass of the reactants compared with the mass of the products should be the same if the reactants are in stoichiometric amounts.

Explanation:

In this question, they ask about chemical reactions and the comparison of the mass of reactants and products. Firstly, it is necessary to introduce the mass conservation principle.

Mass conservation principle mentions that in a chemical reaction, the total mass of reactants is equal to the total mass of products (if the reaction is fully developed). It means mass is not created or destroyed, only transforms from reactants to products.

For example, the mass of sodium plus the mass of chlorine that reactswith the sodium equals the mass of the product sodium chloride.Because atoms are only rearranged in a chemical reaction, there mustbe the same number of sodium atoms and chlorine atoms in both thereactants and products.

Finally, we can conclude that The mass of the reactants compared with the mass of the products should be the same if the reactants are in stoichiometric amounts. 

answer : one can design an experiment using a liquid and an additive that can be added to the liquid and observe the chemical changes in the reaction species.

one would need a beaker which is filled with a known amount of the liquid in which thermometer is placed to measure the temperature changes; after addition of the additive to the liquid solution one can note down the temperature change and find whether the reaction is endothermic or exothermic in nature. by subtracting the initial temperature value with the final temperature one can find the temperature changes.

various combinations of liquid and additive can be used. liquid in this case can be a known quantity of water and additives can be epsom salt or without epsom salt the experiment can be conducted to notice the changes. water and ice, hydrogen peroxide and dry yeast, vinegar and baking soda,etc.

a corroding iron, if that's one of your choices