1.which statement is a correct expression of the law of conservation of mass?
a. the total mass is unpredictable in a chemical reaction
b. the total mass remains the same during a chemical reaction
c. the total mass decreased during a chemical reaction
d. the total mass increases in a chemical reaction

Solution:

The law of conservation of mass states that mass in an isolated system is neither created nor destroyed by chemical reactions or physical transformations.

oAccording to the law of conservation of mass, the mass of the products in a chemical reaction must equal the mass of the reactants.

oThe law of conservation of mass is useful for a number of calculations and can be used to solve for unknown masses, such the amount of gas consumed or produced during a reaction.

Thus the required right answer is B.

six grader is what i am ssorry