Answer:41
Explanation:In a closed system, according to the law of conservation of mass, the total mass of the reactants should be equal to the total mass of the products. Therefore, if Ms. Moore used Substance A with a mass of 16 grams and Substance B with a mass of 25 grams as reactants, the total initial mass of the reactants would be:
Total initial mass = Mass of Substance A + Mass of Substance B
Total initial mass = 16 grams + 25 grams
Total initial mass = 41 grams
According to the law of conservation of mass, this total initial mass should be equal to the total mass of the products. So, the mass of the products in her closed system would also be 41 grams.