TWO solids and a liquid combined in a chemical change. The mass of the final mixture is lower than the mass of the starting ingredients. What happened to the missing mass?

Some of the products may have been gases which escaped from the reaction system.

According to the law of conservation of mass; mass is neither created nor destroyed.

Hence, in a chemical reaction, the total mass of reactants should be equal to the total mass of the products.

When this is not the case, it is possible that one or more of the products of the reaction is or are gases which escaped from the system leading to a decrease in mass of products.

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Some of the mass of the (initial) reactant(s), most likely the water, probably evaporated into the surroundings of where the reaction was taking place.

Explanation:

We know that due to the law of conservation of mass, it is safe to say that most of the time, the mass of the reactants will always equal the mass of the products. When the masses are not equal, that does not mean that some of the mass of the reactants disappeared into nowhere; that would be a violation of the law of conservation of mass. Therefore, the missing mass must have gone into the surrounding environment.

the answer is 303.15 or 303