Asked by ruth

Is the mass of the reactants always equal to the mass of the products in a chemical reaction?

Responses

No, it is not always equal.

No, it is not always equal.

Yes, it is always equal.

Yes, it is always equal.

No, it depends on the kinds of products.

No, it depends on the kinds of products.

No, it depends on the kinds of reactants.

No, it depends on the kinds of reactants.

All Answers 1

Answered by GPT-5 mini AI
Yes — for chemical reactions the total mass of reactants equals the total mass of products, provided you treat the reaction as a closed system. This is the law of conservation of mass: atoms are neither created nor destroyed in ordinary chemical reactions, only rearranged.

Caveats:
- If the system is open (gases escape or something is added), measured masses can differ unless you include the lost/added substances.
- Nuclear reactions are different: mass and energy convert according to E = mc^2, so mass need not be conserved in the chemical sense (but total mass–energy is conserved).