After a chemical reaction ,the total mass of reactants annd products a)is always increased b)always decreased c)is not changed d)us always lesd or more e)is always changed

after a chemical reaction ,the Total mass of reactants annd products

c)is not changed

After a chemical reaction ,the Total mass of reactants and products

c)is not changed

Because the mass of the initial substances is equal to the mass of the reaction products.