Question

an equation for a chemical reaction is shown. naoh + hcl -> nacl + h₂o possible points: 7.69 which statement provides evidence that mass is conserved in the reaction? two hydrogen atoms are in the reactants, and two hydrogen atoms are in the products. two new substances are formed in the products. water is one of the products, but not one of the reactants. one chlorine atom pairs with one sodium atom in the products, and one chlorine atom pairs with one hydrogen atom in the reactants.

Explanation:

The law of conservation of mass states that mass is conserved in a chemical reaction, meaning the number of each type of atom is the same in reactants and products. In the reaction NaOH + HCl → NaCl + H₂O, we need to check atom - counts. For hydrogen, there are two hydrogen atoms in the reactants (one in NaOH and one in HCl) and two hydrogen atoms in the product (in H₂O). This shows that hydrogen atoms are conserved, which is evidence of mass conservation.

Answer:

Two hydrogen atoms are in the reactants, and two hydrogen atoms are in the products.